64 



SCIENCE. 



[N. S. Vol. I. No. 3. 



tlie towns of Diana, Pitcairn and Wilna, 

 but was really a review of the relations of 

 these rocks in a wider region and was based 

 on extended field experience. Peti-ograijhic 

 details were presented of the several kinds of 

 rocks, and especially of the varieties of the 

 anorthosites, which were shown to shade 

 into angite-syenites, and apparently into red 

 gneiss. Many irruptive contacts of anor- 

 thosites and limestone were cited and the 

 location of the classic mineral localities of 

 this region was shown to be along these 

 contacts. The same important thesis was 

 worked out as in the preceding two papers, 

 that the great inti'usions of the Norian se- 

 ries were later than the gneisses and lime- 

 stones. 



The papers were discussed by Whitman 

 Cross, who called attention to the close 

 parallelism of the geology in the Pike's 

 Peak district of Colorado ; and by C. D. 

 Walcott who referred to his own studies in 

 the Adirondacks and similar conclusions to 

 those advanced. 



28. Lower Gambrian Bocks in Eastern Gali- 

 fornia. Chaeles D. WAicOTT, Wash- 

 ing-ton, D. C. 



An account of the discovery of the Lower 

 Cambrian rocks and fauna in the White 

 Mountain range of Inyo County, Cal. See 

 also ISTo. 2 above. This important discov- 

 ery affords a means of correllating the early 

 Cambrian hfe in the remote West with 

 those alreadjr known in the East. 



29. Devonian Fossils in carhonifei'ous strata. 

 H. S. Williams, ISTew Haven, Conn. 

 The paper described the fauna of the 



Spring Creek hmestone of Arkansas, which 

 lies between the Keokuk-Burlington sti-ata 

 below and the Bates^dlle sandstone above, 

 and is at about the horizon of the Warsaw 

 and Chester of the Lower Carboniferous in 

 the Mississippi Valley. The fossils are 

 closely related to the carboniferous fauna 

 described by Walcott from Eui-eka, Nev., 

 and by J. P. Smith from Shasta County, Cal. 



But certain Devonian forms as Leiorhyncus 

 quadricodatum and Productus laehnjmosiis of 

 the New York Devonian are found with 

 them, which are lacking in the jSIississippi 

 Valley, but are found in the Devonian of 

 the West. The interpretation was then 

 made, that the Arkansas fossils indicated a 

 Devonian incursion from the westward. 



Dui-ing the reading of this and the suc- 

 ceeding titles the petrographers reconvened 

 in the upper laboratory, as later recorded. 



30. The Pottsville series along the Neio 

 Biver, West Va. David White, Washing- 

 ton, D. C. 



This paper was a careftil description of 

 the sti-atigraphy of the series, the determi- 

 nations being based on the fossils, which 

 evidence was presented in full. 



31. The Cretaceous Deposits of the Northern 

 Half of the Atlantic Coast Plain. Wm. 

 B. Clark, Baltimore, Md. 



The several formations established as a 

 result of a detailed study of the Cretaceous 

 strata of Monmouth countj^, New Jersey, 

 were shown to have a wide geographical 

 range towards the south. They have been 

 ti'aced throughout the southern portion of 

 that State, while all except the highest 

 members of the series are found crossing 

 Delaware and the eastern shore of Mary- 

 land. Several representatives of these for- 

 mations appear on the western shore, reach- 

 ing to the banks of the Potomac. 



32. Stratigraphic Measurements of Creta- 

 ceous Time. (x. K. Gilbert, Washing-ton, 

 D. C. 



The -nTiter described a great series of 

 Cretaceous rocks, 3500-4000 ft. thick, Ijdng 

 in the Ai-kansas River Valley, west of 

 Pueblo, Colo. Thej' consist of laj^ers of hme- 

 stone 1 ft. to 1 ft. 6 in. tliick, separated by 

 1 in. of shale — this alternation being uni- 

 formly repeated through the whole thick- 

 ness. The wi'iter argued that ft-equent con- 

 tinental oscillation from deep to shallow 

 water deposits was unhkely as having caused 



