412 Mr. E. W. Bray ley, Jun. on the Odour exhaled from 



cal Journal, the temperature of the air in Eschscholtz Bay, rises 

 to above 70 Fahrenheit, and that of the surface of the sea to 

 above 50, the solar radiation rising of course still higher than 

 the air; and the cliffs, consequently, during this season, are 

 constantly thawing. This change of temperature would liberate 

 the volatile matters, and permit the further decomposition of 

 the animal substances attached to or contained in the bones, so 

 as to impregnate the local atmosphere with effluvia, which the 

 succeeding winter would have no power to fix again ; though 

 it might confine them to the vicinity, and prevent their further 

 production until the next summer. 



2nd. Mr. Clift has shown that the bones found in the ca- 

 verns of the Plymouth limestone, which have lost nearly all their 

 animal matter, have probably been deprived of it by the clay 

 with which they are surrounded having absorbed it. (Phil. 

 Trans. 1823, p. 83.) The partial decomposition of the bones 

 from Eschscholtz Bay may have been produced in this manner, 

 and thus the clay in which they are found, may, during the sum- 

 mers which have passed since the deposition of the diluvium, 

 have become impregnated with their animal matter. Or, the 

 animal matter formerly surrounding and attached to these bones 

 may have been absorbed by the clay in the same manner. And 

 in either case, the animal substances being thus in a stale of 

 comparative minute division, mingled with the earthy matter 

 forming the clay, and exposed to the high temperature of the 

 summers, as well as, in the under-cliff, constantly to the opera- 

 tion of the sea-water, would be in the most favourable state 

 for continual decomposition, thus producing the odour in 

 question*. It may further be remarked, that the rapid alter- 

 nations of temperature, during the summer months, from the 



* The view taken by Mr. Clift of the manner in which the bones found 

 in the caves of the Plymouth limestone, have been deprived of their ani- 

 mal matter, and the important connection which the nature of the mud in 

 which the bones are imbedded at Eschscholtz Bay, may have with the 

 circumstances of their original inhumation, show the utility of geologists', 

 when collecting organic remains, being careful to collect specimens of their 

 matrix, also, and not to leave the nature of that to be determined merely 

 by the inadequate means of portions of it accidentally adhering to the 

 fossils. It will be useful, in future, to notice this subject, in instructions to 

 collectors and geological observers, in a more emphatic manner than has 

 yet been done. Specimens of the matrices of organic remains, [it would 

 appear, should be collected, for the express purpose of serving for exami- 

 nation with respect to their influence on the mode of preservation of the 

 latter. 



Chemical analysis should also be resorted to on these points. Thus, 

 the clay enveloping the Plymouth bones, if Mr. Clift's conjecture be well 

 founded, would yield evidence of animal matter, and a similar examination 

 of that in which the bones are imbedded, in Eschscholtz Bay, would be of 

 considerable importance in the elucidation of the origin of the smell ap- 

 parently diffused by them. 



freezing 



