254 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 33 



lines and irregular deposition of sediments the record is incom- 

 plete. Both in England [Cobbold, 1910, pp. 19, 42, and 47] and 

 New Brunswick [Walcott. 1900, pp. 302 and 320-322] the Proto- 

 Iciius fauna [Matthew, 1895, pp. 101-153] has been found beneath 

 the horizon of the Paradoxidcs fauna and above the horizon of the 

 Lower Cambrian fauna. The Protole'mis fauna has a commingling 

 of generic types common to both the Lower and Middle Cambrian 

 faunas, but as yet nothing has been found that could be construed 

 to be a connecting link between the Mesonacidas and ParadoxincC. 

 In the western Pacific Province fauna of China, India, and Australia 

 the genus Redlichia [Walcott, 1905, pp. 24-2C,] appears to be a form 

 that comliines characteristics of both families, and it may be that 

 Alhcrtella [Walcott, 1908a, pis. i and 2] may be found to have re- 

 tained some of the characters of the Mesonacidse ; also Zacanthoides 

 [Walcott, 1908a, pi. 3]. The genus AlbcrtcUa occurs in the passage 

 beds between the Lower and Middle Cambrian or in beds at the 

 top of the Lower Cambrian above OIciicUus canadensis. 



A specimen of the cephalon of Paradoxidcs was found b}' Mr. 

 George Edson [1907, p. 209], of St. Albans, Vermont, in the St. 

 Albans shales just west of the City of St. Albans. The St. Albans 

 shales are argillaceo-arenaceous and carry lentiles of limestone that 

 are more or less fossiliferous. The Paradoxidcs occurs in the shale 

 and in a limestone lentile. Fig. 10 is taken from a compressed ceph- 

 alon in the shale, and fig. 1 1 from a cephalon occurring in the lime- 

 stone lentile along with Agraulos. As far as can be determined 

 from the specimens of the cephalon the species is identical with 

 Paradoxidcs harlani Green from the Braintree quarries near Boston, 

 Massachusetts. 



Mr. H. W. Shimer ' identified under the name "OlcncUits (Holinia) 

 broggeri (Shimer)" a crushed cephalon found in association with 

 Paradoxidcs harlani Green. Through the courtesy of Dr. T. A. 

 Jaggar, of the Massachusetts Institute of Technology at Boston, I 

 have been able to study and photograph the specimen identified by 

 Mr. Shimer and it is here reproduced as fig. 12. Beside it [fig. 13] 

 is an undoubted cephalon of P. liarlani from the same quarry. The 

 Shimer specimen is compressed laterally so as to narrow the glabella 

 and crowd the palpebral lobe inward and out of shape. I find among 

 specimens of the cephalon of P. harlani considerable variation in the 

 length of the palpebral lobe. In some it continues up to the side 



^American Journ. Sci., 4th scr., Vol. 24. 1Q07, p. 1; 



