weeks.] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1895. 53 
28a Lawson (AndrewC). Sketch of the geology of the San Francisco 
peninsula [California]. 
U. S. Gcol. Surv., 15th Ann. Rept., pp. 399-476, pis. v-xii. 
Describes the petrographic character and geologic relations of the 
Montara granite, the distribution and character of the Franciscan 
series, of Mesozoic age, the occurrence of serpentine, and the petro- 
graphic character and distribution of the Pliocene and Pleistocene 
formations. Discusses the dynamic phenomena of the region. 
286 On malignite, a family of basic plntonic orthoclase rocks rich 
in alkalies and lime, intrusive in the Coutchiching schists of 
Poohbah Lake [Ontario]. 
Univ. of Cal., Dept. of Geol., Bull., vol. i, pp. 337-362. 
Describes the field relations of the rocks occurring in the Province of 
Ontario and their petrographic characteristics. 
287 A contribution to the geology of the Coast ranges. 
Am. Geol., vol. xv, pp. 342-356. 
The region described is mainly that of the San Francisco peninsula. 
Describes the relations and succession of the granitic, sedimentary and 
volcanic series. Reviews the paleontologic evidences as to the age of 
the sedimentary rocks and describes the geologic structure of the region, 
and the post-Pliocene diastrophism. 
288 Le Conte (Joseph). Critical periods in the history of the earth. 
Univ. of Cal., Dept. of Geol., Bull., vol. i, pp. 313-336. 
Describes the character of the Glacial, post-Cretaceous, post-Paleozoic 
and prc-Caiubrian revolutions and the general laws of the evohition of 
the organic kingdom and the suddenness of changes and rarity of transi- 
tional forms. 
289 [The genesis of ore deposits.] 
Am. Inst. Mg. Engrs., Trans., vol. xxiv, pp. 996-1006. 
Discusses paper by F. Posepny on the same subject. 
290 Leonhard (A. GL). Origin of the Iowa lead and zinc deposits. 
Am. Geol., vol. xvi, pp 288-294. 
Describes the occurrence and mode of deposition of these deposits and 
reviews the various theories as to their origin. 
291 Lansing lead mines [Iowa]. 
Iowa Acad. Sci., Proc, vol. ii, pp. 36-38. 
Describes the occurrence of lead ore in the Oneota limestone. 
292 Lesley (J. P.), D'Invilliers ( E. V.), and Smith (A. I). W.). [Car- 
boniferous formation, Pennsylvania.] 
Pa. Geol. Surv., Final Rept., vol. iii, part i, pp. 1629-2152, pis. 205-395. 
Describes the characters and distribution of the Carboniferous forma- 
tion in Pennsylvania, giving vertical sections of many localities and 
coal mines, and names and figures many fossils. 
293 Lesquereux (Leo). Cretaceous fossil plants from Minnesota. 
Minn. Geol. and Nat. Hist. Surv., Final Rept., vol. iii, part i, pp. 1-22, 
pis. A and P. 
Gives a sketch of the geologic range of plant remains, and describes 
the plant remains of the Cretaceous of Minnesota. 
