Article J. — Eozooa in Laurentian RocJcs. 
39 
It may be observed also that these crowded clusters of 
columns were often cut off over considerable areas, by thin 
horizontal layers of mineral matter, perhaps indicative of the 
incursion of sand or other sediment, but the growth was 
almost immediately renewed by a new set of columns, occu- 
pying the fresh surface of mud that covered the old ones. 
In the upper part of the reef in which the columns 
flourished and grew, luxuriantly, it is very interesting to 
observe the apparent effort put forward by some of these 
columns to overtop their fellows. Those that grew most vig- 
orously would spread and crowd the adjoining ones, so that 
they were compelled to elevate the centres of their calcareous 
layers. Thus in these crowded columns the layers became 
almost funnel-shaped, while in the broad ones that had plenty 
of room to grow they flattened out to a saucer shape, or in some 
cases are almost entirely flat. It is these funnel-shaped 
layers which, when they are cut across, have the appearance 
of the ends of sticks of wood. They have thus given to 
unpractised observers the impression that the rock consisted 
of crowded masses of wood turned to stone. 
Sometimes one of these columns was quite crowded out of 
existence by its more vigorous neighbors. In other instances, 
we appear to have cases where the columns bifurcated, and 
formed two to occupy space otherwise vacant on the sea- 
bottom. Another feature of these columns which helped to 
carry out the deception that led those who first saw the rock 
to suppose that each column was a stick of wood, was that the 
silicious layers are thinner, and sometimes fail altogether at 
the centre of the column. As the spaces between the calca- 
reous layers are filled up with mineral matter of a darker hue 
than the calcareous substance, the columns appear to have a 
dark centre like the pith of a tree; hence they were thought 
to be trunks of “ hardwood ’’ or exogenous trees. 
This reef of calcareous columns was about one hundred 
and fifty feet deep, but its lateral extent is not known, as it 
is cut off on one side by a fault, and on the other passes 
beneath the waters of the St. John Eiver, and thence probably 
beneath the lower carboniferous sandstones of the Kenne- 
becasis valley. 
