Davidson — Earliest British Brachiopoda. 303 



From the foregoing statements it will be seen that oven with tho 

 small amount of the Gulf-stream directed towards our shores, how 

 great is the benefit we derive from the warmth which its waters 

 impart to our atmosphere throughout the year. If, by a slight altera- 

 ation of the trend of the land, its main body (now to a great 

 extent deflected back upon the N. W. coast of Africa) were compelled 

 to pass northwards into the Arctic Ocean, how enormous would bo 

 the influence it would exert on the climate of Norway, Spitzbergen, 

 and Siberia! — Or, on the contrary'-, suppose the cold northern current 

 to descend on our shores and the full force of the Gulf-stream to be 

 poured upon the shores of Greenland and Labrador, unchecked by 

 the banks of Newfoundland, and any projecting lands ; again, tho 

 Glaciers of these ice-locked lands would recede to their highland 

 retreats, and all the valleys would become clothed with verdure, 

 and be capable of supporting the vegetation of the warmer temperate 

 regions, now only found there in a fossil state. — H. W. 



II. — On the Earliest Forms of Brachiopoda hitherto dis- 

 covered IN THE British Paleozoic Eocks. 



By Thomas Davidson, Esq., F.R. S., F.G.S., etc. 



[PLATES XV. «fe XVI.] 



THE study of the earliest fossiliferous rocks, as well as that of 

 their animal remains, has been, and will be for a long time 

 to come, a subject of very considerable interest, and one that has, 

 especially during the last few years, attracted the keen attention 

 of several experienced and conscientious observers. Many have 

 been the observations assembled in connection with the direct 

 order of superposition and relative age of the various rocks com- 

 posing the Cambrian and Lowest Silurian deposits, as well as in 

 seeking out all the data that could be obtained, so as to enable 

 the palcBontologist to attempt a correct diagnosis of the very earliest 

 known ancestors of many of our fossils. The discoveries effected by 

 Sir W. Logan amongst the ' Laurentian ' rocks of North America (as 

 stated by Sir E. I. Murchison) " constitute the foundation stones of 

 all Palasozoic deposits in the crust of the globe wherever their forma- 

 tions are known ;" and with what keen interest has not the Eozoon 

 been welcomed and elaborated — the oldest animal known ! 



The important discoveries of Barrande amongst the ' Primordial 

 rocks ' of Bohemia have also thrown considerable light upon the 

 life of that remote period, and it is truly wonderful that these 

 animal remains should have been preserved to us in so complete 

 a manner after the countless ages that have elapsed since the time 

 of their final extinction. The creative power seems to have been 

 always in operation, and as one set of organisms had served their time 

 and purpose, they were either gradually or more suddenly modified 

 or replaced by others more suited to the period at which they 

 were called into existence. Now, setting aside the Eozoon as the 



