INTRODUCTION TO CllYPTOGAMTC BOTANY. 101 



Laminm'ia unknown to Europe. The truth, however, is that 

 on a considerable extent of the coast, as far as Cape Cod, the 

 species approximate more than our own to Arctic or sub- Arctic 

 forms. Proceeding to the south the Northern Fuci cease, and 

 are gradually replaced by Sargassuon. The CallitJiamnia and 

 Polysiplionim increase in beauty, Delesseria Leprieurii, a 

 New Zealand species, occurs, and the tropical Bostrychice, one 

 of which is found in company with the last-mentioned species, 

 abound in the estuaries, till, in the Southern states, the forms 

 cease to be those of Western Europe, combining the features 

 of the Mediterranean Algse with those which are perfectly 

 tropical. Species of Caulerpa abound, and numerous allied 

 genera belonging to Mediterranean or West Indian forms, 

 remarkable for the large quantity of calcareous matter de- 

 posited in their tissues. 



82. A long list of fossil Alg,-© is given by Endlicher, com- 

 piled by Unger from the works of Sternberg, Brongniart, 

 Lindley, and others. Such productions, where the determi- 

 nation necessarily dej)ends on outward form only, and not 

 on intimate structure, are always more or less doubtful. 

 The AlgfB most likely to be preserved in a fossil state are 

 doubtless those calcareous species which resemble corals. 

 None such, however, have at present occurred in any geo- 

 logical formation. The genera enumerated by Unger, as far 

 as they resemble in name those proposed for recent Algce by 

 Algologists, will shew the supposed affinity of the fossil 

 species, Confervites, Caulerpites, Codites, Enccelites, Hali- 

 serites, Zonarites, Laminarites, Sargassites, Cystoseirites, 

 Halymenites, Sphcerococcites, Chondrites, Rhodomelites, 

 Delesserites* 



83. Amongst the organic remains contained in amber, none 

 seem certainly referrible to this division, though Algoid forms 

 appear, depending on the motion of bubbles of air in a resisting 

 medium, or other physical causes. The tripoli of tertiary form- 



* An actual inspection of specimens arranged in musenms, under 

 these and other names, leaves an impression that thei'e is not one of 

 them which is rightly referred to Algte. Broken specimens of Oldkamia, 

 an undoubted animal, resemble closely some Conferva. Perfect speci- 

 mens, however, at once ])reclude such an affinity. 



