Ohituanj— Alfred Tylor. 143 



report on Metal- work at the Exhibition of 1862. was translated 

 into German, and also appeared in Swedish. Mr. Tylor sat for 

 some years on the Council of the Geological Society. His Geological 

 papers relate principally to the flow of rivers as connected with the 

 erosion of valleys and the deposit of gravel-beds ; they contain 

 much systematised information, for instance, as to the mechanical 

 action of the Mississippi and the Ganges. It is well known that his 

 study of river-valleys and drift-gravels led him to the hypothesis 

 of a Post-Glacial time of enormous rainfall which he called the 

 "Pluvial Period." The term, though not generally acknowledged, 

 has been found of considerable use, to judge from its not unfrequent 

 appearance in many Geological works. 



Mr. Tylor's paper '• On Changes of the Sea-level and on Denuda- 

 tion " (1853), contains a method of computing the present rate of 

 denudation of the land from the present pluvial and marine action 

 by estimate of the material now being cai'ried out to sea by rivers 

 and removed from cliffs by the sea, and the author contends that 

 there were larger rivers, more rainfall, and greater denudation in 

 former periods. 



In his paper " On the Upper and Lower Valley- Gravels of France 

 and England" (1866), the author enunciated the view that what 

 were termed " High " and '• Low Valley-Gravels," were of one age, 

 and close to the Historical Period. 



His paper in 1868 " On the Amiens Gravel " makes the first 

 definite mention of the "Pluvial Period." 



In Mr. Tylor's paper " On the Quaternary Gravels of England," 

 (1869), he gives a calculation to show that the volume of the flood- 

 waters of the Gravel-Period must have been 125 times greater 

 than that at present in the same valleys, and the volume of the 

 rivers 20 times as large as at present. 



In his paper "On the Formation of Deltas," etc. (1869), Mr. 

 Tylor suggests a rainfall of 300 inches in the Gravel-Period. He 

 also treats of the law of the Parabolic Curve of Eiver -Valleys, and 

 the lowering of the sea-level 600 feet in the Glacial Period, etc. 



In his later years he devoted much time to the consideration of 

 Coloration in Plants and Animals in relation to their structure, as 

 well as to the protective advantages derived by the possession of 

 such colour-markings. 



\x\ future years Mr. Tylor will be chiefly remembered not only in 

 the Society of Friends, but in a far wider circle, as one who had the 

 cause of education most earnestly at heart, and still more for the 

 generous and friendly hand which he was at all times ready to 

 extend to help his fellow-men in any way within his power. 



The following is a List of his Geological Papers : — 



On the Occurrence of Productive Iron Ore in the Eocene Formations of (Hengistbury 

 Head) Hampshire. Quart. Journ. Geol. Soc 1850, vol. vi. pp. 133-134. 



On Chang-es of the Sea-Level Effected by Existing Physical Causes during Stated 

 Periods of Time. Phil. Mag. 1853, vol. v. pp. 258-281 ; Silliman's Journ. 1854, 

 vol. xviii. pp. 21-32, 216-229; Quart. Journ. Geol. Soc. 1853, vol. ix. p. 49 

 (abstract). 



On the Footprint of an Tguanodou, lately found at Hastings. Quart. Journ. Geol. 

 Soc. 1862, vol. xviii. pp. 247-253. 



