March 20, 1885. 



SCIENCE. 



231 



the building, and build large masses of stone or 

 brick upon which piers for delicate instruments 

 could be placed. The conditions for steadi- 

 ness, however, in the Jefferson physical lab- 

 oratory, are fulfilled sufficiently for practical 

 purposes. 



The laboratory, together with its heating and 

 lighting arrangements and engines, cost a hun- 

 dred and fifteen thousand dollars. This sum 

 was given by Mr. Thomas Jefferson Coolidge, 

 on condition that seventy-five thousand dollars 

 more should be raised for maintaining the lab- 

 oratory. Many friends of the university con- 

 tributed to this income fund. 



The laboratory is named in honor of Thomas 

 Jefferson, the ancestor of Mr. Coolidge. Jef- 

 ferson, while president of the United States, 

 evinced great interest in the promotion of 

 university education in America, — an interest 

 which took a practical form in the foundation 

 of the University of Virginia ; and the seed thus 

 sown, it will be seen, bears fruit even unto this 

 day. John Trowbridge. 



EVIDENCES OF BEACHES IN THE 

 CINCINNATI GROUP. 



The presence of old beaches above present 

 water-level is readily perceived on many mod- 

 ern lake and ocean margins, notably around 

 Great Salt Lake and on the Peruvian and Chilian 

 coasts of South America. The evidence of 

 similar beaches in geological groups cannot be 

 considered so decisive, nor is it so conspic- 

 uous. 



That most of the strata of the Cincinnati 

 group were deposited in deep water is proba- 

 ble. The}' contain many fossils whose modern 

 relatives live in deep seas, and it is not likely 

 that it was different with the ancient forms. 

 Brachiopods, crustaceans, biwozoans, polyps, 

 are all inhabitants of comparatively deep 

 water, at least ; and these forms are found in 

 extraordinary abundance in the Cincinnati 

 group. 



Two apparently well-defined shore-lines have 

 been noticed in the rocks in the vicinity of 

 Cincinnati. One of these was first referred to 

 by Dr. Locke some forty years ago. It crops 

 out about three hundred feet above low-water 

 mark, and is characterized by the dumb-bell 

 fossil known as Arthraria. It is apparently 

 to this horizon that Miller refers in the 

 Cincinnati quarterly journal of science, i. 64, 

 where he speaks of wave-lines in the rocks. 

 He savs. — 



"These wave-like rocks are composed in a very- 

 large part of fragments of crinoids, principally of the 

 Heterocrinus simplex, and appear to have been formed 

 by the action of the waves in first breaking to pieces 

 the animal skeletons, and then leaving them in ridges, 

 as if to mark for all future time the course of the 

 waves. These rocks are found in all the hills about 

 Cincinnati, and as far east as Plainville [nine miles]. 

 A number of fossils are found below these rocks 

 that have thus far not been found above them ; and, 

 on the other hand, many have been found above that 

 have not been found below. . . . The fossils which are 

 common to both elevations comprise more than half 

 of all those found below these rocks. And yet, on 

 further examination, it may appear that the causes 

 which led to the formation of these waves in the 

 rocks, also caused a considerable change in the ani- 

 mals which inhabited the ocean at that time." 



Here the probable existence of a shore-line 

 is indicated. It seems to mark one of those 

 periods of elevation which occurred during the 

 deposition of the strata. The fact that many 

 fossils are found above which are not common 

 below, would indicate a serious disturbance of 

 conditions, — a change which caused the ex- 

 tinction of many previously common species, 

 and allowed the introduction of a few entirely 

 new ones. 



It is at about this horizon that rocks bear- 

 ing marks of surface water- washings, and evi- 

 dent traces of the action of trickling water, 

 are found. There are also indications in the 

 rocks of the rippling of water, such as could 

 occur only along the margin of a shallow sea. 

 These marks have been described as Algae 

 under various names, but their true character 

 has been shown by comparing them with modern 

 marks of a known origin. 



A second ancient shore-line, as it appears 

 to be, crops out at various points in the vicin- 

 ity of Cincinnati. Probably the best exposure 

 is at Ludlow, Ky., along the Ohio River, op- 

 posite the city. Professor Orton, in speaking 

 of the waved structure of the rocks, refers to 

 this locality as follows : 1 — 



" The rocks exhibiting this structure at the point 

 named [river-quarries] are the most compact beds 

 of the fossiliferous limestone. The bottom of the 

 waved layer is generally even, and beneath it is al- 



ways found an even bed of shale. The upper sur- 

 face is diversified, as its name suggests, with ridges 

 and furrows. The interval between the ridges varies, 

 but in many instances it is about four feet. The 

 greatest thickness of the ridge is six or seven inches, 

 while the stone is reduced to one or two inches at the 

 bottom of the furrow, and sometimes it entirely dis- 

 appears" (see figure). 



' Geology of Ohio, vol. i. p. 377. 



