302 



THE GEOLOGlSf. 



work to any gentleman who would devote his leisure to them. And 

 the DevH's Bridge, Aberystwith, should be ransacked for fossils ; they 

 are to be found there, yet the age of these rocks is very imperfectly 

 known. 



4. The Cornstones of the Old Eed have some good observers among 

 them ; but there is a great deal yet to be done in these, while there 

 cannot be too many hammerers upon the transition-beds between the Old 

 Bed and Upper Silurian. 



5. The Carboniferous rocks have been well studied, and nothing 

 seems wanting but to follow up, for other districts, the patient work 

 that Dr. Bevan is doing in South Wales, and ascertain, for all the coal- 

 fields, the distribution of the plants in the various parts of the series. 

 I^'ow that the Survey-maps are so far advanced, this is comparatively 

 easy, since no one can be in doubt about the particular beds he is at 

 work upon. 



6. Mr. G. Eoberts' communication, p. 253 of your last number, 

 opens a subject well worth patient investigation — the vegetable con- 

 tents of our own Permian strata, especially the lower beds. While 

 these beds on the Continent are full of peculiar species, in good preser- 

 vation, we, in England, hardly know a dozen specimens of any value 

 from them. 



7. Again, where is the representative of the Muschelkalk, or any of 

 its fossils, in Britain ? 



8. The contents of the Inferior Oolite Sands are yet only partially 

 known. 



9. The transition-beds between the Wealden and the Lower Green 

 Sand, and especially the true relations of that remarkable bed the 

 Chloritic Marl (Craie Chloritee) of the south- east of England, whether 

 with the Chalk Marl above or the Green Sand below, are subjects of 

 great interest. These ought to undergo a rigid examination. 



I have only sketched a few of the many points which might be 

 attempted during this present summer by field-clubs, or by private 

 geologists working for their own amusement. Perhaps if I v/ere to 

 specify two of the more interesting points which deserve notice, I 

 should say — 



Eirst. The contents of the Permian strata in the central counties 

 where the magnesian limestone is absent. Their boundaries are laid 

 down in our new geological maps. 



Second. A full list of fossils from the beds which connect the Car- 

 boniferous with the Devonian system. On this subject I hope to send you 

 a further communication, and can only say, that careful collections made 

 on the two sides of the great Culm-basin of Devonshire, viz., at Barn- 

 staple, North Devon, and at Petherwyn, in Cornwall, would produce 

 good results. We know something of the contents of these from the work 

 of Professor Phillips, and the still earlier researches of Sedgwick and 

 ^lurchison ; but accurate details are wanted from both localities. The 

 old lime-(|uarries at Petherwyn, and more especially the fossiliferous 

 elates associated with them, will require long and continued search 



