Geology and Mineralogy. 481 



surface rocks, or if initially the temperature increased with the 

 depth, the figures given in the preceding paragraph must be still 

 further increased. It follows, therefore, that calculations as to 

 the alleged insufficiency of the contraction theory to produce 

 mountain ranges are at present inadmissible. 



2. Appendages of Trilobites. — As the result of study of some 

 specimens of Triarthrus Bechi, C. D. Walcott has prepared a 

 note on some appendages of the trilobite with a plate illus- 

 trating the structures and diagrammatic restorations of the thoracic 

 limbs. Mr. Walcott shows the antennse to arise from the under 

 side of the head near the postero-lateral angle of the hypostoma. 

 He would make classes of the Trilobita and Merostomata ; 

 the Trilobita and Phyllopod branches diverging from a common 

 Crustacean base of precambrian time, the descendants of the 

 Phyllopod branch being the modern Crustacea, while the Trilo- 

 bita became extinct at the close of the Paleozoic. — Proc. Biol. 

 Soc, Washington, vol. ix, pp. 89-97, PI. i, March 30, 1894. 



3. Geological Surveys in Alabama/ by Eugene A. Smith: 

 The Journal of Geology, vol. ii, pp. 275-287, April-May, 1894.— 

 A brief synopsis of the history of the geological work done in the 

 State of Alabama is given in this article by the present State 

 Geologist. 



4. Tertiary Tipididce, with special reference to those of Floris- 

 sant, Colorado ; by S. H. Scudder (Proc. Amer. Philos. Soc, 

 vol. xxx, 83 pp., Plates i-ix. — In this memoir, presented on the 

 occasion of the celebration of the 150th anniversary of the 

 foundation of the American Philosophical Society, Dr. Scudder 

 has figured and described a series of beautifully perfect crane- 

 flies (Tipulidae) from the Tertiary beds of Florissant, Colorado. 

 Most of the specimens show the venation of the wings and their 

 most delicate markings, and on some of them the fragile legs, 

 thin hairs, the antennas and even the facets of the compound eyes 

 are preserved. 



Some of the more important conclusions reached as a result of 

 the study of this interesting fauna are as follows: The general 

 facies of the Tipulid fauna of our western tertiaries is American 

 and agrees best with the fauna of about the same latitude in 

 America ; all the species are extinct and the fauna is presumably 

 of Oligocene age; no species are identical with described Euro- 

 pean Tipulidse ; eight out of the fifteen genera are extinct ; all 

 the existing genera (except one, Cladura) in the American ter- 

 tiaries are genera common to the north temperate zone of Europe 

 and America, and are either confined to these regions or the vast 

 proportion of their species are so confined, indicating a similar 

 climate, at least there is no certain evidence of a warmer climate. 



w. 



A paper by the same author on the American Tertiary 

 Aphidce, with several beautiful plates, is contained in the forth- 

 coming 13th Ann. Report of the Director of the United States 

 Geological Survey. 



