NOTES AND QUERIES. 



449 



On leaving the Nid, the tonrist may visit Brimham Rocks, which lie among 

 tlie moors on its northern boundary. We crossed over them to Hackfall and 

 Masham ; and our last glance at the purple swells of the healhery moors was 

 one of regret — almost of pain — at leaving the fresh breezes and the wide 

 horizon for the close hot dales and still closer, hotter, smoky towns of York- 

 shire. — Edward Wood, F.G.S., Richmond, Yorkslm-e. 



Plates of Bourgtjetickinus. — Dear Sir, — You vnR find on the accom- 

 panying woodcut figures of extremely rare forms of Apriocrinites, or stem- 

 plates of the crinoid, now more commonly called by D'Orbigny's new generic 

 name of Bourgueticriims, instead of the former term given to these fossils by 

 Miller. 



[Specimens of stem-plates of Bom-gueticrinus from the Upper Chalk of Kent, J 



Fig. c is represented on account of its unusual size. It is from Kent. 

 This is not in my collection, having been lent to me many years since. All the 

 specimens figured on the block, as also others with remarkable articulations in 

 my collection not yet been figured, are from the Upper Chalk of Gravesend. 



In Dixon's Geology of Sussex, table xx., figs. 37, 38, are two stems allied to 

 mine. On reference to Morris's catalogue, page 73, I find other forms besides 

 the B. ellipficus have been published by D'Orbigny and McCoy. — Very truly 

 yours, N. T. Wetherell, Highgate. 



Observations upon Certain Geological Inferences.— Sir, — I have 

 carefully considered the strictures which you have thought proper to append to 

 my communication, for the acceptance of wliich I thank you ; and I am sure 

 that you will allow me some opportunity of extricating myself from the ap- 

 parently unfortunate position in which your remarks have placed me ; which I 

 shall consider in order. 



To say that granite is only a crystalline condition of rock, is just the same as 

 saying tliat ice is only water mums a certain portion of its latent heat. It is 

 rock in this condition which constitutes granite ; and inasmuch as we could 

 not decide whether any given uncrystalUsed rock would become granite upon 

 igneous agency, because we have never experienced the operation, it is useless 

 to talk of any rock which, if subjected to igneous agency, would become granite, 

 not knowing whether such constitutes any portion of the earth's crust. I do 

 not understand your meaning when you say tliat granite may be coeval with the 

 newest of the Tertiary formations. You cannot mean to say that its formation 

 is synchronal with the London clay, for example ? As regards rocks dipping 



