GLACIAL MARINE DELTAS.

1. DELTAS DEPOSITED IN FRONT OF THE ICE IN THE OPEN SEA. This class spread outward in round or irregular fan shape when deposited over broad and rather level plains where they were free to expand in all directions; but in narrow valleys their slopes were necessarily determined in part by adjacent hills. They conspicuously show the characteristic horizontal transition of sediments, from coarse at the north to finer material toward the south, that is, away from the mouth of the glacial river. The delta indications are unmistakable.

2. ICE-BORDERED OR NARROW MARINE DELTAS.-These are usually much longer from north to south than from east to west, having but little of the fan shape. At their southern ends they pass by degrees into clays having the same level, like the delta plains above described. They are found in valleys or level regions much broader than they are, where there is no topographical reason why a delta, if deposited in the open sea, should not have spread outward in fan shape. Evidently the glacial rivers flowed into channels which were open toward the sea, but at the sides were bordered by ice which covered the rest of the valleys and prevented the delta from spreading out.

That these deltas are marine is attested by the marine fossils.

FRINGING LAKE SEDIMENTS.-This class embraces deposits of suspended material brought out from the ice into the bordering lakes by glacial streams and spread over their bottoms. It is a somewhat stratified material of the clayey type, sometimes bearing lacustrine fossils. It is often commingled with stony material dropped by floating ice from the edge of the glacier, but not in noticeable quantities. It is also always commingled with wash from the adjacent land not covered by ice.

BORDERING SEA SEDIMENT.-This class differs from the preceding in the fact that the waters were not imponded in ice, and in the fact that the deposits are commingled with oceanic sediments and marine fossils, and impregnated with saline waters, which may or may not have been wholly removed subsequently.

LOCAL FORMATIONS PRODUCED BY FLOATING ICE.-.These de

posits were laid down by fringing glaciers in lakes (lakes usually formed by glacial damming) or in the ocean.

FOREIGN FORMATIONS PRODUCED BY FLOATING ICE.-These are essentially marine deposits, and are due to icebergs derived from distant glaciers. These bear to the point of deposit material wholly of foreign origin.

SHORE RIDGES DUE TO ICE PUSH.-In the northern latitudes the shore action of ice (not including icebergs) is very noticeable, producing shore ridges of unusual strength.

LITTORAL DEPOSITS.-If we confine the above class to those ridges which were pushed upon shore above the reach of the waters, we need also to recognize a class which was deposited beneath the border of the body of the water, since they were deposited by ice action. To this class is given the name "littoral deposits."

OFF-SHORE DEPOSITS.-These embrace the material of the ice action off shore borne back in suspension or by ice-flows into still waters and there deposited. They must, in the nature of the case, simulate the formations produced by floating ice derived from glaciers (Chamberlin).

DUNES. These are dunes similar to any other class of dunes, except that the material is made up, in part, of grains formed by glacial grinding instead of disintegrated and wave wear, and in their correlation with the ice-border and the glacial waters that issued from the ice, rather than with the sandy shores of lakes and rivers (Chamberlin).

MY EXPEDITION TO THE KANSAS CHALK FOR 1907. By CHARLES H. STERNBERG, Lawrence.

IT

T still remains my privilege to tell this Academy of another successful expedition in the Chalk of Kansas during the past season. My oldest son, who has been my chief assistant since he was twelve years old, feeling that he was perfectly capable of carrying on my work in the field without my presence, insisted on my remaining at home in my laboratory. He promised to keep me busy by sending in new material.

I am delighted to tell you that he did all he promised to, and I was well satisfied with the results. I was indeed kept busy opening boxes and preparing the tons of fossils he sent to me, and it was almost as great a pleasure as to find it myself, without the discomforts attending the actual discovery in the field, to open up to the light a finely preserved specimen collected by the second generation of fossil hunters. He sent me the best specimen of the great ram-nosed Tylosaurus dyspelor I have ever discovered. The entire column, except a few caudal vertebræ, are present, many continuous. And, strange to tell, for the first time the minute last caudal vertebræ are present, the last six measuring a fraction over an inch in length, and the terminal one a mere nodule of bone, less than three-tenths of an inch in diameter. There are about 126 vertebræ, instead of 116, according to the skeleton described by Doctor Williston. So the number must vary, or the last minute ones had been lost in the University specimen. Further, the caudal vertebræ decreased in all their proportions regularly; each one is a millimeter smaller than the preceding one. Consequently, as I believe, the mounted and restored Bourne specimen, in the American Museum, with a short, crooked tail, is abnormal, and not natural, as Doctor Osborn was led to believe. I have another specimen I will mention later, of the same size, in which the tail turns up in the same way that their specimen turns down. Tylosaurus has a long, flexible, eel-like tail.

Another fine specimen sent from the field was a complete skull, with mandibles, of a new species of the Cretaceous seatortoise Toxochelys. This I believe belongs to the new species of which I sent to Yale a couple of years ago a nearly complete carapace and plastron, described by Doctor Weiland as Toxo

chelys bauri. The skull and mandibles are more robust than the principal species, Cope's T. latiremus, wider at the nasal bones, and with round orbits, instead of oblong, as in latiremus. The saggital crest is larger and sculptured.

Another fine specimen discovered was a magnificent plate of Crinoids, Uintacrinus socialis Marsh. This last one went, through the efforts of Mr. Springer, to the National Museum. It contains 150 fine calaces and covers an area of thirty square feet. There is still another fine specimen that I have not seen, but am assured is a complete skeleton, except the head, of Platecarpus coryphaeus Cope. I shall be glad to show you some of these specimens of the life of the Cretaceous, at my laboratory, 617 Vermont street, Lawrence, Kan.

I missed the exhilaration and joy of discovery, and longed to find some excuse to take charge of my party, when I received a letter from Dr. E. Koken, of the museum of the University of Tübingen, Germany. He wrote me that he wished me to conduct an expedition to the Kansas Chalk for his museum, and as he accepted by wire my terms, I have spent nearly three months in his employ. We have enjoyed the most delightful fall weather I have ever experienced in the fossil beds, and our success has been remarkable. We discovered a very perfect

skull of the large ram-nosed Tylosaurus dyspelor Cope. It is four feet in length. I cleaned it so as to show the frontal exposure, and have only seen one skull as large, the one mounted in the Kansas University, discovered by the late Judge West. The one I sold the American Museum is only three feet nine inches long. A singular thing occurs, in connection with this skull, I have never noticed in a Kansas mosasaur before. The end of the ram, or end of the premaxillæ, is missing, and the distal end of the premaxillæ shows the depressions and elevations of one-half the suture, as in the heads of young bones of mammals, and there had evidently been a distinct center of ossification in the ram, that had not yet united firmly with the rest of the bone, and had dropped off. I found fourteen feet of the tail of another individual. There are eighty-six pygal and caudal vertebræ, and a complete pelvic arch with right femur, tibia and fibula, one tarsal and metatarsal. The ischia are directed upward and a little outward; their proximal ends unite with the illia, that lie horizontally with the column; the two pubis bones are out of place, but the right femur and other bones of the limb are in position. This is the first time I have seen these bones in place and they give the height of the illia and ischia, 19 inches; width at the upper ends of the ischia 22 inches, and 20 inches where they join the illia. A great slightly curved basin is thus formed. The ischium is 12 inches long. The illium is 7 inches long where it joins the ischium. The proximal ends of the two bones are not united, but separated by a space of several inches. The pubis is 81 inches long, the femur is 9 inches long, and tibia 5 inches. The length of the preserved limb is 18 inches. The base of the abdomen would have the dimensions of about 20 inches in width and over 30 inches high through the median line-a powerful trunk region, indeed. The tail is a little longer than the body, or about fifteen feet.

To add to our good fortune we discovered a very beautiful skull of Platecarpus coryphæus Cope, with one arch and front limb. The teeth are beautifully preserved and all the bones, evidently, of the head present, though slightly disassociated. A very beautiful open mount can be made of this specimen.

It would occupy too much time to tell of all the material collected within a few miles of Elkader, the center of the richest fossil field in Kansas. But I will close by mentioning the fact that this season I succeeded in securing for Tübingen a