Prof. T. G. Bonney— North- Western Charnwood Forest. 545 



lobes as in ConoMchas and Acidaspis" . He also draws attention to 

 the reduction of the pygidial axis and extension of the limb as another 

 feature in common with the Lichadidae. He seems to suggest that 

 the condition in the latter family is a declension from that in the 

 Bronteidae. But the number of free segments in the trunk is greater 

 and the number of fused segments in the pygidium is smaller in the 

 Lichadidae than in the Bronteidae. The difference here, then, is largely 

 a difference in degree of caudalization. The Bronteidae are not 

 descended from the Lichadidae, but they carry the Lichadid type of 

 organization along lines parallel to and quite as advanced as some of 

 those which characterized the Asaphidae, cf. the isopygous condition, 

 the shifting of the eye close to the glabella and to the posterior 

 margin of the head-shield, the union of the facial sutures with one 

 another in front of the glabella. These facts suggest that the 

 Bronteidae may be provisionally relegated to the sub-order Odonto- 

 pleurida. 



The Proparia. 



The order Proparia is not a large one. It includes the families 

 Burlingiidae, Encrinuridae, Cheiruridae, and Phacopidae. The three 

 last call for no consideration here. 



The family Burlingiidae 1 is of peculiar interest because it 

 carries the Proparia type back from the Tremadocian to the Middle 

 Cambrian. It furnishes a tj-pe in which caudalization (Fig. le), if it 

 has begun, has not advanced beyond the stage seen in the contemporary 

 JParadoxides. The great development of the pleural lobes and of the 

 fixed cheeks which extend to the lateral margin of the cephalon 

 removes this family further than the Mesonacida from the primitive 

 annelidan or arthropodan type of trunk. Though so primitive in its 

 trunk and tail regions and in the position of the pre-ocular suture, the 

 relation of the post-ocular suture to the margin shows no sign of 

 approximation to the opisthoparian condition. On the contrary, and 

 in spite of the specialized position of the eye, it is the same as that 

 found in the early stages of development of other Proparia and 

 the highly specialized as well as the primitive Proparian genera. 

 The points of intersection of the facial sutures with the margin in 

 Burlingia must therefore be regarded as the primeval positions, and 

 can only have been developed directly from the protoparous condition 

 without the intervention of an opisthoparian stage. 



III. — Notes on the North-Western Region of Charnwood. Forest. 2 

 By Professor T. G. Bonney, Sc.D., LL.D., F.E.S. 



CHARNWOOD Forest, since 1891, the date of the last paper by 

 Canon E. Hill and myself, 3 has been investigated by the 

 Geological Survey. Though part of their map and the accompanying 

 memoir have not yet been puhlished, the general results of their work 



1 C. D. Walcott, Smiths. Misc. Coll., vol. liii, 1908. 



2 Bead before the British Association at Manchester, Section C (Geology), 

 September, 1915. 



' Quart. Journ. Geol. Soc, vol. xlvii, p. 78, 1891. 



DECADE VI. — VOL. II.— NO. XII. 35 



