THE 



aEOLOGICAL MAGAZINE, 



No. XXL— MARCH, 1866. 



I. — Oxford Fossils. No. 2. 



By Professor John Phillips, M.A., LL.D., F.E.S. 



(PLATE VI.) 



'0 complete list of the Stonesfield Fossils has been drawn np 

 since 1855, when some remarks of mine on the Geology of the 

 vicinity of Oxford appeared in the first series of Oxford Essays. 

 During the last eleven years we have received from that rich locality 

 many additional specimens, but not many species new to the Uni- 

 versity Museum. One has lately reached my hands which I hope 

 will be of interest to the readers of the Geological Magazine, as 

 adding something to the knowledge of a prevalent group of water- 

 side insects, which has left witnesses of its existence through a very 

 large range of Geological Time, viz. the Neuroptera, and specially 

 the Libellididee. 



On Plate YI. figs, a, h] c, are representations of the specimens, c 

 being an enlargement of the area about the large triangular cell of 

 the wing. Only one wing is really preserved ; but by the splitting 

 of the stone along its plane, the structures are traceable in both 

 specimens, and some help is thus gained for the study of the minuter 

 parts. The state of preservation is good, so that a large part of the 

 network of the wings, between the main somewhat radiating "veins," 

 can be examined, and the whole of the wing-space is coloured nearly 

 of the tint of the yellow-bodied and yellow-winged living species 

 (e.g. Libellula depressa, L. rufescens). This tint is deepened along 

 the main "veins," and serves to mark them very plainly. 



The wing is one inch and three-quarters long, and three-quarters 

 of an inch wide in the proximal part, which is the widest. But it 

 appears to me that a portion of the tip of the wing is concealed in 

 the stone, possibly also a small portion on the posterior edge near 

 the body. The outline to fig. h (Plate VI.) expresses my idea of 

 the full extent of the wing, or nearly so ; for perhaps it is not quite 

 complete at the proximal edge. By these measurements it deserves 

 to be regarded as a broad-winged species, the length of the wing 

 being thrice its width ; while in the large Liassic Aeslma (Brodie, 

 Fossil Insects, plate x. fig. 4) the length is almost four times as great 

 as the width. But that is the anterior wing, and ours appears to be 



VOL. III. — NO. XXI. 7 



