NO. 3 CAMBRIAN TRILOBITES 193 



Lonchocephalus minor differs from L. chippewaensis in having a 

 proportionally shorter more rotund glabella, almost no frontal limb, 

 and usually with a slight incurving of the frontal furrow toward the 

 longitudinal axis of the glabella. 



Formation and locality. — Upper Cambrian: (84) Eau Claire 

 formation; Dresbach, opposite the mouth of Black River, Winona 

 County, Minnesota. 



This is the type locality of the species. 



Also from (79X) Eau Claire formation; near flour mill on Beaver 

 Creek, north of Galesville, Trempealeau County, Wisconsin. 



LONCHOCEPHALUS MINUTUS (Bradley) 



Plate 34, figs. 4, 4a-g 

 Conocephalites minutus Bradley, i860, American Journ. Sci., 2d ser., Vol. 



30, pp. 241-242, text figs. 1-3. (Detailed description of species, with note 



by E. Billings.) 

 Conocephalites minutus Billings, i860. Idem, pp. 242-243 (discussion of 



species), and pp. 337-338, text figs. 40-0. (Additional data on species 



and further discussion of it.) 

 Conocephalites minutus Bradley, i860. Can. Nat. and Geol., Vol. 5, pp. 420- 



421, and text figs. 1-3. (Reprint of paper in American Journal of 



Science noted above.) 

 Conocephalites minutus Billings, i860, Idem, pp. 422-425, and text figs. 



4a-c. (Reprint of two notes in American Journal of Science noted 



above.) 

 Conocephalites minutus Bradley, 1861, Proc. American Assoc. Adv. Sci., 



Vol. 14, pp. 161-163, and text figs. 1-3. (Reprint of paper mentioned in 



first reference.) 

 Conocephalites minutus Billings, 1861, Idem, pp. 163-166, and text figs. ^a-c. 



(Reprint of his two notes mentioned in the second reference.) 

 Conocephalites minutus Hall, 1863, Sixteenth Ann. Rept., New York 



State Cab. Nat. Hist., pp. 150-151, pi. 8, figs. 5-7. (Describes species 



and compares it with C. minor.) 

 Conocephalites minutus Hall, 1867, Trans. Albany Inst., Vol. 5, pp. 134-135, 



pi. 3, figs. 5-7. (Reprint of the preceding reference, with same figures.) 

 Ptychoparia minutus Walcott, 1884, Monogr. U. S. Geol. Surv., Vol. 8, 



p. 91. (Refers to species and places it under Ptychoparia.) 

 Ptychoparia minuta Walcott, 1912, Smithsonian Misc. Coll., Vol. 57, No. 9, 



pp. 267-268, pi. 43, figs. 20-24. (Observations and illustrations.) 



The study of the genus Lonchocephalus has led to its restriction 

 to the form closely related to the type species L. chippewaensis, and 

 this brings Bradley's species minutus under Lonchocephalus. 



It is a small form represented by cranidia and pygidia, and it very 

 closely resembles L. chippewaensis. One of the points of difference 

 is its flattened frontal rim. 



