1844.] 313 



upper part, and the total want of any trace of them in the lower, 

 which led to the lielief that the Timber Creek specimens belong 

 to the genus Montivaltia. 



The total length of the finest specimen (a, see figure), is about 

 1^ inches, and the greatest breadth nearly |- of an inch; the two 

 portions, as before stated, are of about equal length. The whole 

 form of the coral is an inverted cone, terminating downwards in a 

 bent point. The lamelliferous portion is cylindrical, or slightly 

 contracted towards the base, and there is often a tendency to bend 

 to one side. The lamellae are very numerous, amounting probably 

 to eighty ; and are represented in well-preserved sjiecimens by 

 layers of calcareous spar. They were apparently of unequal 

 dimensions ; and their lower terminations are distinctly rounded or 

 semicircular without any signs of fracture, and, consequently, of 

 having extended downwards into the existing hollow cone. The 

 sides of the lamellae were apparently hispid, rows of indentations 

 occurring in the earthy matter, which filled the intervening spaces 

 of the original coral. The superior terminations of the lamellae 

 were unequal, certain of them, probably twenty in all, protruding 

 above the others ; and these range inwards, uniting with the 

 central contorted plates. The characters exhibited in a slightly 

 worn-down specimen prove also that the upper termination of the 

 coral was not cup-shaped, but flat, with possibly a slight central 

 depression (6). 



The centre of the lamelliferous portion consists of plates more or 

 less horizontally contorted in the body of the cylindrical mass, and 

 vertically at the superior and inferior terminations, forming in the 

 latter position either a marked central rugose depression as shown 

 in Dr. Morton's figures (loc. cit.), or a subordinate projecting 

 cone («). 



The interspaces between the original lamellae are occupied by 

 earthy casts, constituting a very conspicuous portion of the coral ; 

 and from their well-defined rounded edge, as well as their decided 

 termination downwards, they might be considered as the true 

 lamellae. It is clear, however, from their bearing the impression 

 of hispid surfaces, that they are mere casts, formed while the 

 original lamellae existed. The material of which they consist is 

 more or less argillaceous, and includes numerous foraminiferte. 



Of the nature of the portion represented by the hollow cone, no 

 opinion can be ofiered. That it possessed a certain amount of 

 solidity, and had structural details which resisted, for a time, 

 decomposition, is evident from the earthy matter which filled the 

 spaces between the lamellae not having penetrated downwards into 

 the cone, and from the marked characters of these casts. It is 

 clear, also, from the preserved vestiges of the crust which en- 

 veloped the lamelliferous portion, as well as from the surrounding 

 cavities mentioned by Dr. Morton, that the external wall or in- 

 tegument must have been thin. 



Locality. Timber Creek. 



A A. 2 



