34 Correspondence — Rev. 0. Fisher. 



formed by fishes and reptiles — that the Articulata alone, of all the 

 Invertehrata, possessed the powers of aerial, terrestrial, and aquatic 

 progression, and in as great perfection as the Vertehrata. 



Mr. Woodward called especial attention to those orders and 

 families of Crustacea which are of greatest interest to the palaeonto- 

 logists, because they are represented, in some instances, far back in 

 time, their remains being found in oldest Palasozoic strata. 



He spoke of those world-wide forms — the bivalve Entomostraca, 

 to which Messrs. Parker, Jones, and Brady, have devoted so much 

 attention, which have lived on from Silurian times to our own : — 

 of the Apus-Yike Crustacea, Ceratiocaris, Peltocaris, Dithyrocaris, &c., 

 equally persistent : of the gigantic Eurypterida, and their modem 

 relatives, the LimuUdce, (these latter appearing, by recent discoveries, 

 to go back in time to the Upper Silurian)^: — of the extinct Trilo- 

 bites and their relationship to Apus and Branchipus. Mr. Wood- 

 ward noticed that aberrant group the Cirripedia, represented by the 

 "Barnacle" and "Acorn-shell," and their relatives, who prefer 

 whales and turtles backs to live on, rather than the sides of ships. 

 He mentioned that one fossil Cirripede had been discovered as low 

 down as the Wenlock limestone, and that the fossil shell, of a species 

 parasitic on the whale, had been found in the Crag of Suffolk, where 

 such vast quantities of the bones of fossil Cetacea are also met with 

 in the Coprolite-diggings in the Crag. He then spoke of the higher 

 forms, the Decapod Crustacea, represented by the Crab, Lobster, and 

 Prawn, and showed that the short-tailed Crabs have, at present, only 

 been found as far back in time as the great Oolite, but that the long- 

 tailed type go back to the Coal-measures. 



In conclusion he strongly recommended this group to the attention 

 of Town-members, as, from the London Clay, some of our finest 

 Tertiary fossil Crustacea had been obtained ; whilst from the Chalk 

 of Kent and Sussex and the Gault of Folkestone, an equally abun- 

 dant harvest might be procured. 



Mr. Woodward's lecture was illustrated with a large series of 

 Diagrams and Specimens of recent Crustacea, serving to show the 

 wonderful diversity of form and modification of the appendages 

 which are displayed in so remarkable degree by this interesting class. 



coI^I^ESI=OIs^l^E^:^^CE. 



DENUDATION, AND ITS AGENTS. 



Sir, — T am pleased to find that your contributors have of late re- 

 turned to the attack upon the difficult subject of denudation. There 

 is plenty of room for other workers to labour in other departments 

 of our illimitable science, without this subject being lost sight of. We 

 must be content to undergo a good deal more hard thinking and close 

 reasoning upon it. Fine writing will not solve our difficulties. Even 

 alliteration may fail to help us. 



Denudation has been going on for extended ages, and this pecu- 



* See the first article in the present number of the Geological Magazine, p. I. 



