184 
Notes . 
several grounds ; they are considerably more ancient than any 
members of the genus previously described, they are the first English 
specimens recorded, they are preserved in a more complete and 
perfect form than any others at present known, and lastly, the greater 
simplicity of their structure causes the essential characters of the 
genus to stand out with greater clearness than in the more complex 
species. The specimens were discovered by Mr. G. Wild and 
Mr. J. Lomax, in material from the Hough Hill Colliery, Stalybridge. 
The sections have been cut, with the greatest skill and success, by 
Mr. Lomax, and are very numerous, about 100 sections, transverse 
and longitudinal, having been examined from one specimen alone. 
The principal specimens are four in number, in addition to which 
other fragments have been included in the investigation. The species, 
which is very distinct from any form previously described, will be 
known as Medullosa anglica ; a diagnosis is given below. 
The most complete specimen of the stem has a mean diameter of 
rather more than 7 cm., including the adherent leaf-bases. The others 
do not appear to have been very different in dimensions. 
The large leaf-bases, to judge from the most perfect specimens, 
almost completely clothed the surface of the stem. They were de- 
current, and confluent with the stem for a vertical distance of 13 cm. 
or more ; the diameter of the petiole, where it became free from the 
stem, being about 3 or 4 cm. The arrangement of the leaves was 
a spiral one, and in the only case where the phyllotaxis could be 
determined the divergence proved to be f. 
In two of the specimens the external characters of the fossil are 
well shown. The external surface of the long leaf-bases is marked 
by a conspicuous longitudinal striation, the ribs (which would not 
have been so prominent during life) representing the fibrous strands 
of the hypodermal tissue. The habit of the stem, clothed with the 
long, almost vertical, overlapping leaf-bases, may have been not unlike 
that of some of the tree-ferns, such as Alsophila procera . 
The vascular system of the stem consists of three (or locally four) 
steles, anastomosing and dividing at long intervals. Each stele has 
an elongated, somewhat irregular, sectional form, and is composed of 
a central mass of primary wood, surrounded by a zone of secondary 
wood and phloem. The primary wood, which is very well preserved, 
is made up of tracheides and conjunctive parenchyma, with the spiral 
elements (protoxylem) scattered near its outer margin. The secondary 
