38 SCIENCE PROGRESS. 



An examination of the testimony of the rocks to the 

 existence in past ages of Algal forms is therefore a process 

 of general interest to biologists and to all who are concerned 

 with the subject of evolution. The most superficial con- 

 sideration of the matter will result in the recognition of the 

 high degree of improbability that attends the chances of 

 preservation of such delicate structures as the cell-walls of 

 Algae. Acquainted as we are with the marvels of preserva- 

 tion of minute structure in many plant fossils, exhibiting 

 even cambial cell-walls as in a newly cut section of a living 

 plant, there must yet be borne in mind the rarity of such 

 conditions in geological history, and their limitation, with 

 a few exceptions, to the case of terrestrial vegetation, though 

 aquatic agencies may have operated in its preservation. 

 Prepare ourselves as we may by such antecedent considera- 

 tions, a revelation of the scantiness of the record comes with 

 an uncomfortable shock, and the object of this article will be 

 attained if the shock act as a stimulus to the undertaking of 

 new searches for material in the older rocks, since the bare- 

 ness of the record is doubtless due in part to the want of 

 enterprise of this kind. There is a disposition to be con- 

 tent with the reflection that the older the organism the 

 simpler it must be and therefore the less likely to be pre- 

 served to us, that the very absence of such forms from fos- 

 siliferous strata is an eloquent comment on their character, 

 that there is no use fighting against the malignant conspir- 

 acy of natural forces to obliterate the vestiges of early life, 

 but such a disposition is a truant one and inconsistent with 

 the progress of palaeontology in general. 



By the researches of Nathorst (i and 2) the ground has 

 been cleared of the debris of many spurious fossil Algae de- 

 scribed by Brongniart and other older writers under the 

 names of Chordophyce<z,Arthrophycece, Rhixophycece, Spongio- 

 pkycecE, DictyophycecE, Keckia, Munsterza, Oldhamia, Eophy- 

 ton, Discophorites, Gyrophyllitcs, Chondrites, Confervztes, 

 Catderpites, etc. A considerable number of such forms 

 were thus confidently described and assigned definite places 

 among the Algae by writers who must have had vague 

 enough notions of the outward forms of the living organisms. 



