Hi Jesse,

A slight variant, "janmanā jāyate śūdraḥ," is traced to the Skanda Purāṇa, Nāgara-khaṇḍa 239.31 on the website linked below. The author of the website article includes a screenshot of a published edition with the text highlighted, but does not give any information about the edition of the text. Still, I hope it is a helpful lead.
http://www.harekrsna.com/sun/editorials/05-14/editorials11673.htm

Ted Benke also quotes the passage in his dissertation (p. 267, see link below), saying that it is "attributed to Manu," citing Radhakrishnan.
http://repository.upenn.edu/cgi/viewcontent.cgi?article=1133&context=edissertations

Best,
David
--
David Buchta
Lecturer in Sanskrit
Department of Classics
Brown University

On Sun, Sep 11, 2016 at 4:49 PM, Jesse Knutson <jknutson@hawaii.edu> wrote:
>
> Dear Indologists and Friends, A friend and colleague, Ramdas Lamb, has drawn my attention to, and asked me about the source, of a half-verse, which he has heard quoted a lot in Ramanandi circles in India.  He is doing some very interesting ethnographic work on the evolution of this order, and told me about several inter-caste, Vedic पाठशालाs they have recently established, incorporating sometimes even dalits, women, and adivasis.  I have a feeling one of you knows the source. Thanks for your time. भवदीयः,J  
>
> जन्मतो जायते शूद्रः संस्काराद्द्विज उच्यते
>
>
> --
> Jesse Ross Knutson PhD
> Assistant Professor of Sanskrit and Bengali, Department of Indo-Pacific Languages and Literatures
> University of Hawai'i at Mānoa
> 461 Spalding
>
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