Identifier: panamericangeolo141894desm (find matches)
Title: The Pan-American geologist
Year: 1922 (1920s)
Authors:
Subjects: Geology
Publisher: Des Moines, Iowa : Geological Pub. Co.
Contributing Library: University of Illinois Urbana-Champaign
Digitizing Sponsor: University of Illinois Urbana-Champaign

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rystalline limestones of Jenny Jumpmountain are in all eases sharply distinct from the blueCambrian limestones ; and at the locality where the two occurnearest together, there is no gradation in lithological charac-ter between them. Conclusion. In conclusion, the crystalline limestones ofWarren county are believed to be distinct from and older thanthe blue magnesian limestone of Cambrian age which occursalong the northwestern side of the New Jersey highlands.They are believed to be distinct for the following reasons:first, they have a well developed crystalline character, andthey hold large quantities of accessory metamorphic minerals;second, they show no intimate association in areal distribu-tion with the blue Cambrian limestone; third, they show notendency to grade into blue limestone. They are believed tobe older, because, first, they have been subjected to generalmetamorphic forces resulting in great changes, of which theneighboring blue limestones show no trace; second, they oe-
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Brontichthys clarki^from the Cleveland shale.—Claypole. 379 cur in intimate association with the granitoid gneisses and insome cases appear to be interbedded with them. Whether the other ciystalline limestones of New Jersey areof the same age as those of Warren county, has not beenproved. The answer has generally been that they are. Thisseems to be the most probable view. If the) are, and if theposition taken in the present paper is valid, then the eiwstal-line limestones of Sussex county, and of other places in NewJersey, would also be, as they have generally been supposedto be, of pre-Cambrian or Archaean age. (PaL.EONTOLOGICAL Nc ITES FROM BlCHTEL COLLEGE.—NO. 8.). ON A NEW PLACODERM, BRONTICHTHYS GLABKI,FROM THE CLEVELAND SHALE. By E. W. Claypole, Akron. Ohio.(Plate XII.) To the three great placoderms of the Upper Devonian ofOhio, Dinichthys, Titanichthys, and Gorgonichthys, must nowbe added a fourth genus not less remarkable than the rest andonly less striking because it is n

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