POPULAR MISCELLANY. 



285 



history of geology. While these faunas are 

 remarkable for the great number and vari- 

 ety of the species and individuals, and also 

 for the enormous size of some of their 

 forms, it is in other directions that their 

 highest interest lies. Tiy their anomalous 

 and altogether unexpected characters, by 

 their strange combination and dissociation 

 of peculiarities of structure, they throw a 

 flood of light on the question of evolution, 

 and give us a key to the development of the 

 existing creation that, before their discovery, 

 it was too much to expect we should ever 

 possess." The most important service, Pro- 

 fessor Orton further remarked, that has 

 been rendered in the American field, is the 

 recent mapping of the great moraine from 

 the Atlantic border to Dakota. On "the 

 unfinished problems relating to the geology 

 and chemistry of coal," Professor Orton enu- 

 merated the four principal theories of the 

 formation of coal-beds, inclining to favor 

 the peat -bog theory of Lesquereux and 

 Brongniart. In accounting for coal-fields — 

 a succession of coal-beds separated by ma- 

 rine formations and inorganic sediments of 

 sandstone and iron-ore — we have to seek an 

 explanation of the regularity of the inter- 

 vals, and are referred to CroU's theory of 

 an astronomical cause. Various unsettled 

 questions also appear on the chemical side ; 

 and, while much has been done, much re- 

 mains to be done in the field of the micro- 

 scopical structure of coal. These problems 

 will probably all be solved, but when that 

 is done, " out of these old carboniferous 

 swamps, new questions, larger, deeper than 

 any we now see, will perpetually arise to 

 stimulate by their discovery and to reward 

 by their solution that love of knowledge for 

 its own sake which makes us men." Cap- 

 tain E. L. Corthell presented a paper, which 

 was read at a general meeting, on the con- 

 tractions of the earth's crust and surplusage 

 in mountain-structure. New discoveries of 

 fossils in the older strata of various regions 

 were announced. Professor Henry S. Will- 

 iams presented a paper on the comparative 

 stratigraphy of the southern counties of New 

 York and the adjoining counties of Penn- 

 sylvania, and Northern Ohio as far as Cleve- 

 land. Professor E. W. Claypole discussed 

 the problem of the origin of the paleozoic 

 sediments of Pennsylvania. Professor Lewis 



E. Hicks described the structure and rela- 

 tion of the Dakota group in Nebraska. Mr. 

 G. K. Gilbert described an old shore-line of 

 Lake Ontario, which he had traced half-way 

 about its basin. Professor A. R. Crandall 

 described some small volcanic dikes which 

 have recently been discovered in Elliot Coun- 

 ty, Kentucky. Professor Orton described the 

 gas and oil wells of Northwestern Ohio, in 

 the region of which Findlay is the center, 

 and whose sources of supply are in forma- 

 tions lower than any from which gas has 

 been known before to issue. The flow of 

 gas ranges in the various wells from 100,000 

 to 1,200,000 cubic feet per day. The pe- 

 troleum is not very abundant, and is black, 

 sulphurous, and of a gravity of about 35°. 

 The formation whence the gas and oil issue 

 is a porous magnesian limestone identified 

 as Trenton. Professor A. C. Worthen de- 

 scribed the quaternary deposits of Central 

 and Southern Hlinois as observed in cutting 

 coal-mine shafts through them. The bed- 

 rock surface is diversified by valleys much as 

 the drift surface above, but with a different 

 drainage system. At the bottom is a strati- 

 fied clay, in part gravelly, which appears to 

 be derived from the waste of the bed-rock. 

 Above this is a forest-bed, which, though 

 not a universal feature, is so widely spread 

 as to make much of the well-water unfit for 

 use. Over this lies a blue and yellow grav- 

 elly clay, with glaciated bowlders sometimes 

 as large as two feet in diameter ; and, finally, 

 a few feet of loess, covered with a thin bed 

 of fine clay. 



Educational Masenms. — Dr. Burt G. 

 Wilder, addressing the Biological Section 

 of the American Association on "Educa- 

 tional Museums of Vertebrates," maintained 

 that every institution, of whatever grade, 

 should have one. In selection quality is 

 more important than quantity, and ar- 

 rangement is usually more needed than 

 acquisition. As a rule, each specimen 

 should teach but one thing, and that thor- 

 oughly. The same form may, therefore, 

 properly recur in several parts of the mu- 

 seum, to illustrate different parts or ideas. 

 True economy consists in paying liberally 

 for what is wanted, rathfr than in taking 

 what is not wanted as a gift. " In addition 

 to, or in place of, the three great series — 



