32 Remarks on the Decay of 



lated, layer over layer and growth over growth, until the mass 

 contributes to form an entire mountain, and you will have one 

 more subject for contemplation in addition to the innumerable 

 others which result from an enquiry into '* the remains of a 

 former world." R. C. Taylor. 



LewistowUi Mifflin County, Pennsylvania, 

 Nov. 2. 1833. 



Art. IX. Remarks and Illustrations on the Decay of the Stems 

 of succulent Plants. By Frederick C. Lukis, Esq. 



The fossil vegetables which are found in the secondary 

 formation, designated as coeval with the consolidation of the 

 sandstone and coal measures, present to the eye of the ob- 

 server patterns of great beauty and regularity, and display 

 figures which have been often compared wuth the eccentric 

 ornaments of ancient architecture. 



Without entering into the general geological hypothesis, 

 much may be done, in the study of these interesting remains, 

 by close investigation and analogy ; and, indeed, the nature of 

 fossil vegetables must receive its principal elucidation from 

 the careful examination of existing species analogous to them, 

 when they can be found. 



The physiological botanist is well aware that plants in 

 decay are disposed to shrivel up, each in a manner peculiar 

 to its own class, and that this operation is governed by their 

 internal as well as external organisation, and by the circum- 

 stances under which they may be placed. 



As the greater number of our fossil plants have been 

 referred to the ferns, cactuses, and other succulent analogues, 

 it is among these we are to look for characters of resemblance ; 

 and although many of these remains possess dimensions which 

 baffle our conceptions, when brought in comparison with our 

 pygmy tribes of the present economy, still the latter, in- 

 significant as they appear, may aflPord us physiological types 

 sufficiently clear to bring us near the truth. A series of 

 observations made on the drying and decomposition of suc- 

 culent plants has occupied my attention for many years, 

 and I propose to notify some of the changes remarked in the 

 stems and branches of the ASempervivum arb^reum L., or 

 tree houseleek, as it is called, in the course of their decay. 

 They will suffice to show the variety of patterns which may 

 be produced, under favourable circumstances, by a single 

 individual of the succulent class. The result of decay 

 in stems of this plant has been the production of exterior 



