14 A Fossil Alga. 



Caitlerpites of which I have seen specimens and figures, there is not one 

 which might not with equal propriety be assigned a place elsewhere within 

 or without the vegetable kingdom. 



With due consideration of all these facts, I yet propose to submit 

 reasons for believing that we have a veritable fossil Caulerpa represented 

 by specimens from the Kimmeridge clay. This fossil was discovered 

 by Mr. Damon, of Weymouth, and described * by him as an Equisetaceous 

 plant. He sent specimens to Mr. Carruthers, who very kindly placed 

 them in my hands for description, with the remark that they might 

 prove to be a true Caulerpa. I have examined other specimens of this 

 fossil in the Geological Department of the British Museum, and am 

 much indebted to the Director-General of the Geological Survey for the 

 permission to use and figure here (plate V., fig. I) an excellent specimen in 

 the Museum of Practical Geology, first pointed out to me by Mr. E. T. 

 Newton. These specimens represent a cast in the round (not a flattened 

 impression) of a verticillate organism. We are, therefore, on much safer 

 ground in describing it than we should be in dealing with a mere impres- 

 sion. In some specimens the hollow interior of the axis is now filled in 

 places with a solid substance crystallised from the minerals dissolved 

 in the water. The specimens come from a bed of marine origin, and 

 we may assume, without absolutely excluding other possibilities, that 

 the remains represent a sea-weed, if a plant at all. No zoologist has 

 been forthcoming who will claim it as an animal, and on the other hand 

 there are strong positive reasons for believing it to be an Alga. In the 

 first place, the stature, habit, and mode of branching favour this view, 

 and the correspondence with existing species of Caulerpa is so close, 

 that, were such a specimen clothed with cellulose walls and endued with 

 living contents to be placed before a phycologist, he would have little 

 hesitation in assigning it a place near Caulerpa cactoides, Ag. From this 

 species, in point of fact, the specimens in question differ in one single 

 respect of outward structure, viz., in the fossil we have verticillate ramenta 

 in place of the opposite pairs or, as it may be said, whorls reduced to two 

 members of the living species. In the lower whorls of the fossil (plate IV., 

 fig. 2) there are thirteen ramenta in each whorl, and the number diminishes 

 towards the apex. In plate IV., fig. la, there is a whorl which must 

 be near the apex of a specimen exhibiting only six. The ramenta are 

 constricted at their insertion, and are club-shaped in form, as in C. cactoides. 

 Unfortunately we do not have the creeping surculus. The following may 

 be taken as a description of the species, with which I have much pleasure 



* Supplement to the Geology of Wey mouth, Portland, and Coast of Dorset, 1888. 

 Plate xix., figs. 12, \2a. 



