66 Seward. — A Contribution to our 
measures 2 9 cm. in the widest part. Seen in longitudinal 
section, the pith shows here and there somewhat irregular 
and more or less transverse bands of dark- coloured tissue 
which, on superficial examination, resemble the horizontal 
disks of the pith of Cordaites (PL V, Fig. 2). Other sections 
of the same block were afterwards found in the Museum, and 
finally additional preparations were recognized in the William- 
son Collection as having been obtained from the large piece 
of stem. From the entries in Professor Williamson’s Catalogue 
of microscopic sections it was found that the material came 
from the Coal-Measures of Oldham, and had been contributed 
by Mr. Nield. The specimen when intact must have been 
one of the largest ever found in the English Coal-Measures in 
which the internal structure had been preserved. 
In the fourth of the series of Memoirs on the ‘ Organization 
of the Fossil Plants of the Coal-Measures’, Williamson writes as 
follows with regard to a specimen referred to Lyginodendron : 
‘ I have obtained from Mr. Nield one magnificent axis in 
which the woody cylinder and its contained medulla has 
been at least eighteen inches in circumference. The thickness 
of the wall of this vascular cylinder has been at least 
2i inches ; and, since the specimen is weathered and water- 
worn, it may have been of even larger dimensions.’ In 
a foot-note the specimen is said to have been ‘ found in a 
watercourse intersecting the Lower Coal-Measures at a locality 
near Oldham known as Har Culver (Higher Culvert) 1 .’ In 
the recent memoir on Lyginodendron and Heterangium by 
Williamson and Scott, the authors refer more than once to 
Nield’s large specimen. Discussing the size of Lyginodendron 
stems, these authors write : ‘ The largest undoubted stem of 
Lyginodendron which we possess attained a diameter of about 
4 cm. We leave out of consideration for the present both 
Mr. Nield’s specimen and the cortical impressions. These 
must have belonged to stems of enormously greater size, but 
1 Phil. Trans., 1873, p. 386. A radial section of this specimen is figured in 
Plate XXIII, Fig. 9 (No. 1183 i n the Williamson Collection). 
