Correspondence. 385 
The next terrane is the Little River group which contains the plant 
beds of the "fern ledges." To the stratigrapher it appears absurd to 
speak of these being equivalent to the Pottsville conglomerate (i. c., the 
Millstone grit) in age. 
Lest it might be thought that the reference of the plant beds of 
St. John to this low horizon, rests only on the writers' early determina- 
tions, supported later by Drs. L. W. Bailey and R. W. Ells, he may 
say that Sir William Dawson went over these sections before he wrote 
his classic papers and reports, wherein he referred them to the Middle 
Devonian. Dr. T. Sterry Hunt also spent a good part of one season 
in examining the southern coast region of New Brunswick with Dr. L. 
W. Bailey and the writer ; and Dr. Selwyn when Director of the Can- 
adian Geological Survey, went over the same ground ; as he gave the 
imprimature of the survey report to the view above expressed, it is to be 
presumed that he was satisfied with the evidence in its favor. 
The fact of the matter is that Mr. White has read the biology of the 
plant bed fiora from the wrong end. A few of the ancient types of 
this flora (Archseopteris) were known when Rogers made the first 
geological survey of Pennsylvania. And since Dawson studied the 
flora other types have been gradually gathered from the lower horizons 
of the Carboniferous : Megalopteris for instance was found in several 
species in Ohio by professor Andrews from the lower coal measures, 
and later Lesquereux described others, gathered chiefly in the south 
and the Mississippi states from the equivalent of the Maunch Chunk red 
shale. It would appear that a number of the species of this flora sur- 
vived in Pennsylvania until the time of the Pottsville conglomerate. 
The reference of these plant beds to the Millstone grit reminds one 
of the persistency with which Lesquereux some thirty or forty years 
ago clung to the view that the Lignite beds of the west were of 
Tertiary age, whereas it has been amply shown by the marine fossils 
that they are Cretaceous. 
Many genera of plants have a wide vertical range; witness the 
recent genera, Anientacese &c., in the Cretaceous, some species of 
which are very difficult to distinguish from modern forms; is the Cre- 
taceous recent because it contains these? Some species of marine 
forms (Brachiopods and Trilobites even) range through a whole geo- 
logical system, why may not some plants ? 
To recapitulate, the following changes occurred between the depo- 
sition of the St. John plant l)eds and the formation of the Millstone 
grit. 
Ero.sion of strata to the Niagara horizon with deposition of the 
Mispec tcrranc. 
Crushing and folding of the unconsolidated terrancs from (and in- 
cluding) the Mispec downward. Extrusion of granite. 
Deposition of the Albert shale and congloinerate=Pt)coKO. 
Erosion to the Laurentian or Fundamental complex, with deposition 
of red slate and (•(in.trloiiifrato=:.lAnn/(7/ Chunk. 
