1Q(J MR. IIATCHETX'S OBSERVATIONS 



Its ftrata agrrc ft may however be proper to obferve, that the Bovey coal 

 ft br° d ' s ^ oun< ^ in ft ra(a » correfponding in almoft every particular 

 with thofe of the furturbrand in Iceland, deferibed by Von 

 T-roil*, and by Profelfor Bergmann f. The different ftrata 

 of both thefe fubftanees are likewife fimilar, being compofed 

 of wood or trunks of trees, which have completely loft their 

 cylindrical form, and are perfectly flattened, as if they had 

 been fubjected to an immenle degree of preiTure ;£. 



The 



* Von Troil's Letters, p. 42. 



f OJiufcula Beigmaum, Tom. III. De Products Foicaniis, 

 p. 239. 



\ Bergmann, in the diftertation above quoted, accurately de- 

 fcribes this appearance of the furturbrand, and then fays, " Qua? 

 autem immanis requiritur vis, ut truncus cylindricus ita compla- 

 netur ? Nonne antea parti cularum nexus Jiutredinis quodam gradu 

 fuerit relaxants? Certe, nifi compages quodammodo mutatur, 

 quodlibet pondus incumbens huic effe&ui erit impar. Ceterum 

 idem obfervatur phenomenon in omni fchijlo argillaceo." This is 

 certainly a very curious fact ; and the learned ProfefTor, with his 

 ufual acutenefs, rejects the idea that mere weight can have been 

 the caufe. As a farther proof alfo, he afterwards obferves, " Or- 

 thoceratitai, quae in Jirato calcareo conicam jiguram Jierfecle fervant, 

 in fchifto Jilanum fere triangidare comjirejfwne efficiunt. Idem valet 

 de pifcibus, conchis, inieftifque petrefactis." And again, " Ob- 

 fervatu quoque dignum eft, quod idem refterialur ejfeclus, quamruis 

 firatum calcareutn fub jclvfto c olio catv.m fit, et majori idco fiondere com- 

 [irimenle onnjiuniy Dt- Produclis Foicaniis, p. 240. It is evident, 

 therefore, that weight alone has not produced this effect ; and 

 Bergmann's idea, that the folidity of the vegetable bodies may 

 have undergone fome previous change, in the manner of incipient 

 putrefaction, by moifture, and by becoming heated in the mafs, 

 muft be allowed to be very probable. But bodies fuch as fhells. 

 could not be thus affected j and therefore they mull have been ex- 

 poled to fome mechanical effect, peculiar to argillaceous ftrata - r 

 tvhich efife^t, however, from the circumftances which have been 

 adduced, evidently could not have refulted from the mere preffure 

 of the fuperincumbent ftrata. To me, therefore, it feems not 

 very improbable, that, together with a certain change in the foli- 

 dity of vegetable bodies, produced in the manner imagined by 

 Bergmann, and, together with fome degree of fuperincumbent 

 pre Hiiro, a real and powerful mechanical action has been exert- 

 rd, by the contraction of the argillaceous ftrata, in conference 



of 





