376 Reports and Proceedings — 



in Brazil."^ By C. B. Brown, Esq. With an Appendix by R. Ethe- 

 ridge, Esq., F.E.S., E.G.S., and communicated by him. 



The author in 1874 had the opporti;nity of examining some beds 

 on the Solimoes, or Upper Amazon, and the Javary, one of its 

 tributaries, containing fresh- and brackish- water shells similar to 

 those found in Tertiary deposits at Pebas, still higher up the river. 

 The author indicates certain errors into which he considers previous 

 writers to have fallen, and calls attention to the great extent of 

 these beds, now demonstrated to occupy a tract of country 300 miles 

 in length by 50 miles in breadth, and to the enormous change in 

 the physical features of the region which must have taken place 

 since their deposition. "When this took place, the sea reached pro- 

 bably 1500 miles west of its present shore-line, covering the 

 country which is now the valley of the Amazon. The absence of 

 examples of false-bedding in the deposits leads him to the con- 

 clusion that they were formed in comparatively still water, into 

 which flowed numerous streams bearing much vegetable matter, 

 which has served for the formation of lignitic deposits, the whole 

 being probably the upper beds of a series deposited under similar 

 conditions to those of deltas in the present day. In an Appendix, 

 Mr. Etheridge notices the fossils collected by the author, which 

 included seeds of Char a, and species of Mytilus (1 new), Anisothyris 

 (4, 1 new) , Liitraria (1), Thracia (1), Anodon (1), Unio (1) Natica? 

 (1), Neritina (2 new), Odostomia (1), Hydrobia (1 new), Isaa (1), 

 Dyris (1), Assiminea (1 new), Fenella (1), CeritJiitim (2 new), 

 Melania (4 new), and a new Gasteropod constituting a genus 

 (Alycaodonta) allied to Alycceus. A single palatal plate of Myliobatis 

 or Zygobatis (probably derived) was also found. 



8. " On the Physical History of the English Lake-district, with 

 Notes on the Possible Subdivision of the Skiddaw Slates." By J. 

 Clifton Ward, Esq., Assoc. E.S.M., F.G.S. 



The author traces the physical history of the lake-district from 

 the commencement of the period when the Skiddaw slate was 

 deposited. To this succeeded the volcanic Borrowdale series, which 

 is followed after a physical break by the Coniston Limestone. 

 Between this and the succeeding Silurian deposits there is little, if 

 any, break. Thus, in the Lake-district, the break between Upper 

 and Lower Silurian is physically below the Coniston Limestone, 

 though palaeontologically it is above it. 



The Old Eed Sandstone period was one of denudation, which was 

 continued into the Carboniferous period ; and perhaps the whole 

 district was actually covered by the sea during the maximum 

 depression of the Lower Carboniferous epoch. Since then it has 

 probably never been submerged, but exposed to continuous subaerial 

 denudation. The physical significance of the Mell Fell (Lower 

 Carboniferous) conglomerates receives special attention. 



The author, from consideration of the amount of deposition and 

 rate of denudation, attempts to estimate the period which has 

 elapsed since the commencement of the record, and sets it down 



^ On this subject see paper by Dr. H Woodward, in Ann. & Mag. Nat. Hist. 

 1871, ser. 4, vol. Tii. pp. 59 and 101, pi. v. 



