ON A GIGANTIC FOSSIL FUCUS. 
188 
moment are so actively engaged in forming sub-marine strata along the shallow 
shores of our tropical seas, hereafter to be raised from the bosom of their waters 
by Nature’s dynamics. 
Nunekam House , Cheltenham , 
Nov. 12, 1838. 
ON A GIGANTIC FOSSIL FUCUS DISCOVERED IN THE NEW 
RED SANDSTONE AT WOODSIDE, ON THE RIVER MERSEY. 
By the Rev. Thomas Dwyer, M.A. 
This extraordinary fossil was discovered in a stratum of the New Red Sand¬ 
stone at Woodside, Cheshire, on the West bank of the River Mersey, opposite 
Liverpool. It is situated on the shore at about high-water mark, and has been 
brought into view by the weathering of the rock exposed to the action of the 
sea-water, and other causes. The rock in which the fossil is embedded seems to 
be the upper portion of a stratum of the New Red Sandstone; it is of a yellowish- 
white colour, fine-grained, and of moderate hardness. It is free from pebbles. 
The dip of the rock is a few degrees, not more than six or seven, to the North- 
East. It is probable that the rock has been little, if at all, disturbed since its 
deposition; for we know that many strata are now deposited by the sea slightly 
inclined to the horizon. The stratum in which the fossil is embedded is a por¬ 
tion of the variegated Sandstone, or lower division of the New Red Sandstone 
formation, corresponding to the Gres bigarre of Continental geologists. There 
can be very little doubt but that the fossil is of marine origin. It is most 
analogous in its appearance to the Fuci of our shores at the present day. It is 
of considerable thickness, has the same flat ribbon-like shape, and the same 
irregular mode of growth. 
The position of the fossil is similar to the position of a Fucus left by the 
receding tide. Two parts now separate appear to be upper portions of the same 
plant; and there seems likewise to be a distinct plant, from the lower portions of 
which a number of shoots or side branches issue. In the central portion of one 
of the former («. e ., the now separate parts of a once single plant) the side 
branches have disappeared, in consequence of the rock being much worn away by 
persons continually passing over it. 
The termination of the lower portion of the specimen is abrupt, owing to a sea 
wall having been built to prevent the encroachments of the tide on the adjacent 
property. 
