Correspondence — Dr. C. Callaway — Mr. H. Woods. 377 



He makes it quite clear that in his criticisms of my work at 

 Malvern he had employed the theological, rather than the scientific, 

 method. I had often said that a gradation between two kinds of 

 rock at Malvern proved the derivation of the one from the other ; 

 but then I had previously explained, by an accumulation of details, 

 what I meant by a Malvern gradation. Mr. Blake forgot the 

 details, and suggested that I believe any kind of gradation would 

 prove my case. It is possible to involve any author in apparently 

 contrary opinions, if his sentences may thus be detached from 

 their context. 



But Mr. Blake goes on to admit that he does not really suppose 

 me to hold the opinion that " if one rock passes into another, one 

 of them is dei'ived from the other," but he does think I argue ou 

 the basis of the following : " The character of the stages by which 

 one rock passes into another in the field may suffice of itself to 

 prove that one of them is derived from the other." This is quite 

 another thing, and should have been said at first. 



Mr. Blake's use of my illustration of the beef cooking before the 

 fire is rather misleading. The roasting meat undergoes a change, 

 and so do the Malvern rocks during metamorphism. The cook is 

 able to observe the change, and so can the geologist at Malvern. 

 These two points exhaust the analogy as I limited it, and to expand 

 it to cover a special theory of metamorphism is to commit a fallacy 

 in logic. 



My critic — perhaps I may say " critics," for Mr. Blake follows in 

 the wake of others — appears to think that no amount of microscopic 

 or outdoor evidence will suffice to prove the conversion of a diorite 

 into a quartzose gneiss (not "quartz-schist," as Mr. Blake inaccurately 

 writes). If this opinion be right, we are shut up in eternal darkness 

 on this question, ior no other proof is available. Surely, our 

 ignorance of the chemistry of high temperatures and great 

 pressures ought not to be erected into an insuperable bar against 

 the reception of good field-evidence. Are my critics going to wait 

 until earth-forces can be inti"oduced into the laboratory ? 



■Wellington, Salop. C Callaway. 



BOULDERS IN A COPROLITE BED AT STANBBIDGE. 



Sir, — A bed of " coprolites " is now being worked near Stanbridge, 

 in South Bedfordshire, at a spot about half a mile west of the church, 

 just in the angle formed by the roads from Leighton Buzzard and 

 Billington. Tlie bed resembles in many respects the Cambridge 

 Greensand ; its thickness varies within short distances, the maximum 

 being about one foot. Fossils are not abundant, but those found 

 belong to species which occur in the Cambridge Greensand. Mr. 

 Jukes-Browne made a fresh survey of the district some ten or eleven 

 years ago, and determined that the bed, which was at that time 

 exposed in some other pits in the neighbourhood, occurred at the 

 base of the Upper Gault, which in this district is very marly, 

 yielding over 50 per cent, of carbonate of lime. 



Two boulders of quartzite have recently been found in the 



