ALG. 3 
remains, originally mentioned as species of the genus Algacites, are 
referred to various recent genera to which some resemblance in 
external form is considered to exist. The name Algacites has since 
been replaced by other terms, and appears to be no longer used 
as a general designation of fossil A/g@ of doubtful affinity. There 
is another term, Fucotdes, which has also been used by Sternberg 
and many other palobotanists in an equally wide sense, but such 
a name naturally suggests a certain resemblance to the recent 
genus Fucus, and is thus unsuitable if used in a more com- 
prehensive sense. 
This suggestion as to the use of a provisional and wide generic 
designation, such as Algites, may be considered a retrogressive 
step and likely to lessen our accurate knowledge of fossil Alye. 
If the data were generally adequate, and afforded sufficient 
indication of botanic affinity, any such term would be superfluous. 
When we consider how exceptional it is to find ourselves in a 
position to make definite statements, founded on satisfactory 
evidence, as to the family of Alge@ in which fossil forms should be 
placed, it must be admitted that we are lessening the possibilities 
of error by the return to more gencral and less definite terms. 
Botanists would naturally prefer to pass over such markings 
or casts which are too imperfect to admit of identification; but in 
spite of their apparent worthlessness from a botanical point of view, 
they may be of service to the geologist, and indeed the most 
fragmentary material may become important when more perfect 
specimens have been discovered. Thus it is better to place on 
record even those exceedingly doubtful fossils, and to adopt a 
provisional name in the hope that future discoveries may throw 
more light upon family or generic affinity. Generic names, such 
as Sphenopteris, Pecopteris, etc., of Brongniart have served a most 
useful purpose, and by degrees these are being replaced by more 
definite botanical titles as fertile specimens are discovered, and so 
afford clues as to natural affinity. As another instance of a 
convenient term we may mention Fachiopteris, which Williamson 
has applied to those fragments of fern petioles which it is not 
possible to refer to particular genera. 
