246 RECORD OF SCIENCE FOR 1887 AND 1888. 



New England by Pumpelly, in the Grand Canon region by VValcott and 

 Powell, in Central Texas by Walcott, and iu some other parts of the 

 country. Irving was disposed to separate the series into two groups, 

 each co-ordinate with the Devonian, Silurian, Cambrian, etc. — viz, the 

 Keweenawan and Huronian, — and to class the entire series as a great 

 system co ordinate with the Paleozoic, for which he proposed the term 

 Agnotozoic* The present disposition among leading American geolo- 

 gists is, however, to reduce the series to the taxonomic rank of the 

 groups (Devonian, Silurian, etc.), and to combine its divisions under the 

 name Algonkian. 



Second iu importance to the recognition of the Algonkian must be 

 placed the discovery in Texas during 1887 of a series of Cretaceous de- 

 posits underlying the Dakota formation (the supposed base of the cre- 

 taceous in this country), which is paleontologically equivalent to the 

 lower half of the European cretaceous. The bridging of this break iu 

 the history recorded in American sediments is due to the labors of Hillt 

 and C. A. White. | The evidence upon which the conclusions of these 

 investigators rest is largely paleontologic, and their discovery is of in- 

 terest to paleontologists as well as geologists. 



Another noteworthy event, also of interest to the paleontologist, while 

 at the same time important in statigrai)hy, is the elucidation of the 

 structure of the Taconic Mountains in western New England, largely 

 by Walcott, during 1887 and 1888. There is in eastern New York and 

 western New England a region of faulted and metamorphosed crystal- 

 line or subcrystalline rocks, generally deeply mantled by drift, which 

 has been theintellectnal battle-ground of nearly all American geologists 

 given to controversy for over half a century. In the early forties some 

 of these rocks were erroneously grouped, and efforts were made to give 

 this fictitious group a place in systematic geology under the name 

 "Taconic system" and the " Taconic question" has been before the geo- 

 logic world from that day almost to this. Late in 188G, and again in 

 1887, Walcott visited the region, and after much labor discovered the 

 defective arrangement, ascertained the true relations of the strata, and 

 made public his conclusions. In this work he was greatly aided, by the 

 results of careful field studies extending over many years, by the emi- 

 nent geologist of Yale, James D. Dana. The careful work in the field 

 by Dana and Walcott has however been criticised. The contributors 

 to the subject during the biennial period include Hunt, Marcou, Miller, 

 Newberry, Vogdes, A. Winchell, N. fl. Winchell, and others. But to 

 the geologist interested in substantial progress rather than polemics, 

 and to the layman interested in the practical results of geologic investi- 

 gation, the most satisfactory contribution ever made to the "Taconic 



*7th Aun. Rep. U. S. Geol. Survey, 1888, p. 453. 

 t Am. Jour. Sci., a'oI. xxxiv, p. 288, ami elsewhere. 

 \ Proc. Nat. Acad. Sci. Phil., 1887, pp. 39-47. 



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