1855.] 



GEOLOGY IN AMERICA. 



60 1 



They are compound animals of the family Ei'yozoa, the lowest type 

 of the class MoUusca. They consist of a kind of radiating frame 

 apparently covered in whole or in part with a kind of web, so as to 

 resemble the rays and cloth of a parasol. But they do not radiate 

 from a centre, but from two ends of a line by bifurcation or tri- 

 chotomy, so as to preseivc a bilateral symmetry. The separate rays 

 only have generally been observed, which have been referred to 

 Cephalopoda or Kadiata. They appeared to be txihes with one or 

 two rows of serratures on their edges. The Professor now regards 

 these notches as each a part of a simple anim.al, and that where 

 there is but one row of serratm'cs visible, it is because they are 

 so folded as to hide the other. 



Prof. Agassiz thought the case before us a good example of the 

 difiiculties with which the fossil zoologist has to contend. Who 

 would ever make out the structure and use of this tool (the para- 

 sol) by finding only single sticks of one ? The difiiculty is greater 

 in a compound animal, for if a man substituted the laws that hold 

 a community together for the physiological laws that prevail in the 

 human system, he would go widely astray. But Prof. Agassiz had 

 met something very like the Graptolithus among the marine animals 

 of Key West, furnished him by the Coast Survey. And here we 

 find a further instance of the fact that ancient races, extinct in the 

 Eastern Hemisphere, are still represented by a few species in the 

 New World. 



The Mauvaisea Terres. — Professor James Hall gave some account 

 of the Geology of Nebraska and the Mauvaises Terres. The country 

 on the Upper Missouri River — Nebraska — he said, had been known 

 to us for many years. Until witliiu a few years past our know- 

 ledge had been derived from Lewis and Clark, Nicolay and some 

 others. All these had brought specimens from Nebraska, from which 

 we had learned that for a great distance along the Jiissouri river, 

 beginning at the mouth of the Platte, and extending several hun- 

 dred miles northerly, there was a cretaceous formation, the most 

 prominent fossils of which were Ammonites and Bacculites. All 

 had shown that this existed in a largely developed scale, but with 

 tlio exception of Nicolay, no attempt was made to establish sub- 

 divisions. In 1847 we had for the first time a published notice of the 

 existence of an extensive tertiary formation in that region, given by Dr. 

 Prout, of St. Louis. This was, however, to the West of Missouri. Sub- 

 sequently Jlr. Culbertson brought collections, and Dr. Owen directed 

 Sir. Evans to make collections, from which we had a pretty good 

 knowledge of tertiary and its mammalia. Mr. Hall's principal ob- 

 ject in making collections was not to make discoveries of new species, 

 but the investigations of Dr. Owen did not tell us whether there 

 were distinct formations or not, and moreovei" it seemed .an impor- 

 tant consideration that the flora corresponding to the ancient faaua 

 should be known. That was not accomplished by the expedition, 

 but we had some more details with regard to the tertiary and creta- 

 ceous fofmations. In the neighborhood of the mouth of the Platte 

 the carboniferous formation terminated. Passing up the Missouri 

 we found that the carboniferous passed into cretaceous. At their 

 junction was a sandstone which might perhaps be older than tlie cre- 

 taceous. Upon it lay a buff calcareous rock, which would mark like 

 clialk, containing scales and jaws of fishes. Above this was a great 

 thickness of clays which contained most of the species that had been 

 brought from this part of the country. A thinner bed above the clay 

 was characterized by a Large baculites. Those subdivisions extended 

 over the western country, and we had yet to seek their cliaracteristic 

 fossils. The species already described already amounted to betiveen 

 tliirty and Ibrty, and he had about an equal number of new species. 

 At a considerable distance west of the Missouri the cretaceous beds 

 began to dip slightly to the west. Above the bed characterized by 

 baculites and 80 miles west of the Missouri commenced the tertiary, 

 at first containing no fossils, but about 80 miles furtlier on there 

 were paheotherium and fossil turtles within twenty feet of tlie creta- 

 ceous, although tlic tertiary nearer the river was 50 or GO feet high. 

 They concluded, therefore, that the beds were unconform.ablc, the cre- 

 taceous dipping westward and the tertiary being deposited horizon- 

 tally upon it, so that tlie eastern tertiary began to be deposited when 

 the western was already 250 feet thick. The mauvaises terres were 

 formed of this tertiary extensively deinided. Two new species of 

 mammals had been discovered, one of them allied to the musk deer 

 and the other 11 small carniverous animal. lie was indebted to Mr. 

 Meek and Mr. Hayden for the specimens which he exhibited. The 

 shortest term to express the character of Nebraska was to say that it 

 was a perfect desert, incapable of .Nujipnrting men or animals except 



in a migiatory condition. The buffaloes came in the spring with 

 the grass, and went away in midsummer when it was gone, and tlie 

 Indians followed them. There was almost no wood ; some few 

 shrubby willows, and a cotton-wood a foot in diameter was always 

 known as the big cotton-wood, and now that it was gone the place 

 was still called Big Cotton Wood Spring. Pui-e water was rarely 

 met with. There were occasionally some springs in the baculite 

 formation which commenced 75 miles west of the Jiissouri. The deep 

 cl.ay beneath it was almost impassable. In the spring it was all mud, 

 and in the summer the clay cracked so as to dxaw out the roots of 

 vegetation and destroy it. Along the bottoms were occasionally a 

 little good soil, but it was not valuable. This clayey soil was dark, 

 but not with organic matter. lie had seen in Mr. Meek's notes that 

 night after- night he was compelled to camp witli bitter water, and 

 send out the men to gather a few stunted willows or cotton-wood for 

 fire. Most of the water was impregnated with saline materials ; 

 and as all the water in the Mauvaise Terres contains sulphate of 

 magnesia, the party was compelled to submit to its medicinal effects. 

 Southward toward the Platte was some better land but little wood. 

 Kansas was much like Nebraska, and the climate was such that in a 

 great part of the territory it would be difficult for New England men 

 to exist. He knew that Nebraska w:is a desert, and would remain so 

 for all time to come. [This curse of barrenness does not apply to the 

 settled portions of Kansas. They are carboniferous.] 



On the Polishing of Granite hy Driving Sand. Hg Mr. Wm. Make. 

 — A short paper on the cutting and polishing of granite by driving 

 sand in the Colorado Pass, was read by Mr. Blake, who exhibited 

 specimens of the grooves and channels, as well as of the polished sur- 

 face of the I'ock. The wdiole surface of the granite in the pass, he 

 said, was cut into long and beautiful grooves, which had a fine polish. 

 Even quartz was cut away and polished by the incessant action of the 

 sand. Garnets imbedded in feldspar stood out and protected the 

 feldspar behind them. The little fingers of stone thus produced all 

 pointed to a constant west wind drawing through the pass. This 

 grooving and polishing might be seen in all parts of the desert where 

 there were rocks to be acted upon. The polish was not like that of 

 the lapidary, but looked more astliough the rocks had been oiled or 

 varnished. Some of the grooving and polishing which had been 

 ascribed to glaciers, might perhaps be referred to this cause. 



Prof. Agassiz said that he was particularly interested in these phe- 

 nomena, since he had devoted so many years to the study of the gla- 

 ciers. To know that there was another series of phenomena similar 

 to the glacial was very interesting, and suggested caution in ascribfhg 

 any apparent phenomenon to either the one or the other cause. He 

 was pleased to see that no objection had been made to the possibility 

 of glaciers having produced similar phenomena, and that their ex- 

 istence was acknowledged by Mr. Blake. It became necessary to 

 distinguish the two sets of phenomena. Sand in order to be moved 

 over such surfaces must be of very nearly uniform size. Now in the 

 glacier we had two different phenomena produced simult-aneously ; 

 one was the polishing of the surfaces, and the other the grooving and 

 scratching produced by the larger masses of rock in the glacier. These 

 features were certainly snfticient to distinguish between glacial action 

 and the wearing of currents of sand. 



Coal Fields of Missouri and Illinois. — Prof. Hall expressed an 

 opinion that about three-fourths of the Missouri and Illinois' coal 

 fields marked out by Owen would have to bo wiped off the map, and 

 its place supplied by silnrian, with its pentamerus, oblongus, and 

 other characteristic fossils. He liad seen lower silnrian and upper 

 Silurian fossils over large area.s of Owen's coal fields. He supposcil 

 most of that coal to be outlaycrs resting iu basins, and having no con- 

 nection with each other. 



Gi!Olo;;y Iu America* 



An Address delivered before the American Association for the Advance- 



menl of Science, assenxbled at Providence, Rhode Island, AuffMt 



nth, 1855, Ay Professor James D. Da.na. 



In selecting a topic for this occasion, I have not been without per- 

 plexity. Before an Association for the Advancement of Science — 

 Science in its wide range — a discourse on the progress of science -in 

 America for the past year wouM seem legitimate. Vet it is a fact that 

 original memoirs in must departments, published within that period, 

 would make a very meagre list. Sloreover, it is too much to expect 



