IN THE STRATA OF THE LIAS AND OOLITIC SERIES. 59 



transverse sections of fossils found in the same deposits, I shall first de- 

 scribe them. They are represented in Plate XIV., and are uniformly en- 

 larged in the proportion of 55 to 1, excepting Fig. 6, which is of the natu- 

 ral size. 



Fig. 1. Portion of a transverse section of fossil wood from the upper 

 lias, near Whitby, to the south. This wood is in concentric layers, which, 

 viewed by transmitted light, are umber-brown. The layers are separated 

 by calcareous spar, so as to present a broken and confused appearance. The 

 portion represented is one of the most regular, being from near the margin, 

 where the layers are occasionally contiguous. 



Fig. 2. This figure represents part of five layers near the centre of the 

 same fossil. The irregular interruptions of the structure are filled with 

 calcareous spar, and are not lacunae, of which there are no traces in the 

 regular portions. One of the most remarkable differences in the organiza- 

 tion of this fossil is the great difference in the breadth of the woody layers. 

 Another is the difference in the texture, Fig. 1. presenting distinct medul- 

 lary rays ; while Fig. 2. wants them, being from a portion in which they 

 are not observed. Fig. 1. also appears very different from Fig. 2. in the 

 size and form of the cellules, but this difference arises solely from the cir- 

 cumstance, that the latter is from a thicker portion of the slice, similar dif- 

 ferences in thickness producing corresponding differences in appearance, in 

 the slices of recent plants. 



Fig. 3. Portion of a slice of fossil wood from the lias near Whitby. In 

 this wood the concentric layers are very distinct, although, in some places, 

 they are variously distorted. This figure represents one of the most regu- 

 lar portions. 



Fig. 4. Represents a distorted portion of the same. There are hardly 

 any traces of medullary rays iu this fossil, which is in general remarkable 

 for the regularity and little breadth of its concentric layers. 



Fig. 5. Portion of a section of fossil wood from the lias near Whitby. 

 In this wood the concentric layers are very large and regular. It is espe- 

 cially remarkable for the regularity of the medullary rays, which present 

 few intersections, but appear like continuous tubes. 



