o/" Ulodendron to Lepidodendron, &c. 163 



Specimen No. 2. From Straiten Oil Shales, near Edin- 

 burgh (Caiciferous Sandstone Series). — This example is 

 a fragment of what must have been a large stem. The 

 specimen, which is an impression in very fine-grained 

 bituminous oil shale, measures 9 inches in length by nearly 

 8 inches in breadth. Towards the centre are shown two 

 Ulodendroid scars, about ly\ inches long, by l^V inches 

 broad, standing rather less than 1^ inches apart. This 

 example is chiefly interesting from the absence of the 

 longitudinal fissures which are so characteristic of these 

 Ulodendroid stems. As a consequence, from the increase in 

 girth of the stem, the leaf-scars are much broader than in 

 those examples where the bark is longitudinally fissured. 

 This specimen shows a similar change in the lateral extension 

 of the leaf-scars to that w ich occurs in the older stems of 

 Lepidodendra which do not bear Ulodendroid scars. The 

 leaf-scars on this fossil are very similar in general form to 

 the figure of Sagenaria Veltheimiana given by Romer in 

 ' Palaiontographica,' vol. ix. pi. iii. fig. 6, only in the 

 British specimen their breadth is greater in proportion to 

 their length ; they are, in fact, nearly as broad as long. 



Specimen No. 3. From the Oil Shales, West Calder, Mid- 

 lothian (Caiciferous Sandstone Series). — Specimen in the 

 collection of the Addiewell Oil Co., Addiewell. PI. IV. 

 fig. 2. — This figure shows a portion of a large stem of Lepi- 

 dodendron Veltkeimiamwi, 25 inches long and about 4 inches 

 wide. The greater part of the fossil shows the outer surface 

 of the stem, on which are exhibited, in a very early state of 

 development, three Ulodendroid scars and a part of a fourth. 

 The Ulodendroid scars, from centre to centre, are 5^ inches 

 apart. They are slightly elevated, and do not show a clearly 

 defined umbilical nodule, having an appearance as if the 

 appendicular organ had been forcibly removed. In this early 

 condition of development of the Ulodendroid scar, the appen- 

 dicular organ appears to have been attached at its upper 

 margin. Another "interesting point shown by this example 

 is the presence of the ordinary leaf-scars on the Ulodendroid 

 scar. These are a continuation of the ordinary series of the 

 leaf-scars on the stem, and converge from all sides to the 

 centre of the upper margin of the slight inflation. As there 

 is here the outer surface of the stem, it is clearly shown that 

 in the elementary condition the part bearing the appendicular 

 organ stood at a slightly higher level than the rest of the 

 bark. This inflation, however, eventually became effaced by 

 the increase of the stem causing the bark to swell up around 

 tlie base of the appendicular organ, and by this means the 



