Report of the State Geologist. 247 



0. strophomenoides, Hall, 1857 = Orthostrophia strophomenoides. 



O. subsequata, Conrad, 1843. Trenton. 



0. subcarinata, Hall, 1857. Lower Helderberg. 



O. subcircula, Simpson, 1889. Clinton. 



O. subelliptica, White and Whitfield, 1862. Kinderhook. 



0. subjugata, Hall, 1847. Syn. for O. occidentalis. Hall. 



O. subnodosa, Hall, 1879. Niagara. 



O. suborbicularis. Hall, 1858. Hamilton. 



O. subquadrata, Hall, 1847. Hudson Kiver. 



0. suhumbona, Hall, 1857 = Spirifera subumbona. 



O. swallovi, Hall, 1858. Burlington. This species agrees in all 

 characters, except size, with O. resupinata (Martin's species) as figured 

 by Davidson. 



0. sweeneyi, N. H. Winchell, 1881. Trenton. 



O. tenuidens. Hall, 1852. Clinton. 



O. tenuilineata. Hall, 1843 [Atrypa ? tenuilineata]. Chemung. 

 ? 0. tenuistriata, Hall, 1843. Portage. This is not an Orthis; probably 

 a Lamellibranch. 



O. testudinaria, Dalman, 1827. Trenton to Hudson River. 



O. thiemii, White, 1860. Chemung and Kinderhook. 



0. tioga, Hall, 1867. Portage and Chemung. 



O. tricenaria, Conrad, 1843. Trenton. See 0. disparilis. 



O. trinucleus. Hall, 1852. Clinton. 



O. triplicatella, Meek, 1872. Hudson River. 



O. tritonia, Billings, 1862. Quebec. 



0. tubulostriata. Hall, 1857. Lower Helderberg. 



O. tulliensis, Vanuxem, 1842. TuUy. 



0. uberis, Billings, 1866. Anticosti. 



0. umbonata, Conrad, 1842 = Amboccelia umbonata. 



0. umbraculum, Owen, 1852, Hall, 1858 (non von Buch). Syn. for 

 Derbya keokuk. Hall. 



0. unguicidus, Hall, 1843 ^^non Phillips). Syn. for Ambocoelia 

 gregaria. Hall. 



0. unguiformis, Castelnau, 1843 and Emmons, 1860. Syn. for 

 Hipparionyx proximus, Vanuxem. 



O. vanuxemi, Hall, 1857. Corniferous to Hamilton. 



O. vanuxemi var. pulchella, Herrick, 1888. Middle Waverly, 



O. [Bilobites] varica, Conrad, 1842. Lower Helderberg, 



O. whitfieldi, N. H. Winchell, 1881. Hudson River. 



The families of Strophomenidse and Productidse have not yet been 

 sufficiently determined in their relations to each other, or to other 



