AME£ICA. 115 



Berthond, E. L. • On the Occurrence of Uranium, Silver, lion, &c. 



in the Tertiary Formation of Colorado Territory ; with Notes by 



Dr. G. A. Koenig and l/Lr. Gabb. Froc. Ac. Nat. Sci. Fhiladd. pt. ii. 



pp. 3G3-366. 



Describes the Lyden coal-mine. The mineral vein appears to take 



the place of a Tertiary coal-bed. 



Bradley, Prof. Frank H. On the Silurian age of the Southern Appa- 

 lachians. Amer. Jouni. ser. 3, vol. ix. pp. 279-288, 370-383. 

 A detailed description under the following heads : — 1. Introduction ; 

 2. Silurian of East Tennessee ; 3. From Athens to Murphy ; 4. From 

 Knoxville to Murphy ; 5. The Marble Belt. — Thinks that the *' pyro- 

 crystalline " and " Taconic " rocks of the Blue llidgc region are pro- 

 bably all Silurian iustead of being Azoic or Laurcntian ; also that the 

 uplift and metamorphism of all this region took place in post-Carboni- 

 ferous times. G. A. L. 

 Brockway, Charles J. Mineral deposits in Essex Co., Mass., especi- 

 ally in Newbury and Newburypcrt. Pp. 60, map. 12mo. Niw- 

 huryport. 

 Brown, Charles B., and J. G. Sawkins. Reports on the Physical, 

 Descriptive, and Economic Geology of British Guiana. Pp. iv, 

 297 [paging of pp. 3, 4 repeated]. Plate (sections), Map in pocket, 

 49 woodcuts. 8vo. London. 

 General Report on the Physical, Descriptive, and Economic Geology. 

 Pp. 5-30. I. General Physical Features. II. General Descriptive 

 Gcologj', with details of well- sections. III. Economic Geology, with 

 analyses of soils, list of heights, and Catalogue of Rocks and Minerals. 

 Then come separate Reports on Districts as follows : — 1, Report of the 

 N.W. portion of British Guiana, 31-37. 2. Cuyimi and Supinaam 

 JRivers, 38-44. 3. Puruni and Mazaruni Rivers, 45-51. 4. River 

 Demerara, 52-55. 5. A portion of the Essequebo River, and of the 

 Pacaraima Mountains, 50-74. G. Excursion from Georgetown to Mapuri 

 Rapids, &c., 75-95. 7. Rewa and Quitaro Rivers, &c., 96-107. 

 8. Central Portion of British Guiana, 108-129. 9. District bordering 

 on the Curiebror}', &c. Rivers, 130-201 . 10. Corentyne River, 202-232. 

 11. Berbice and Demerara Rivers, 233-255. 12. Mazaruni River, 

 256-257. The Kaietur Waterfall is reported on in pp. 278-297. " It 

 is produced by the Potaro River flowing over a sandstone and conglo- 

 merate tableland into a deep valley below, with a total fall of 822 

 feet," 741 of which are in a i)erpendicular column. The 3 sections are 

 on the same scale horizontally as the map, 13-6 miles to an inch. The 

 map, dated 1873, has 9 colours, the divisions being Alluvium, Sand and 

 Clay, Sandstone, Greenstone, Schist and Gneiss, Hornblende Rock, Quartz 

 porphyry and Felstone, Granite and Syenite, and Quartz. W. W, 

 Chapman, Prof. E. J. An OuUino of the Geology of Ontario, based 

 on a SubdivJHion of the Province into six Natural Districts. Can, 

 Jonm. n. st r. vol. xiv. pp. 580-588. 

 Gives a general outline of the geological features of tho Province, 



i2 



