Juan González de Hermosillo

Has anyone heard of this book "Venerable libro de la Cofradía de Santiago de Burgos", it contains all the ancestors of the González de Hermosillo at least in the male line back to the 1200's. I think we should track this book down. I think there is only one in the actual Caterdral de Burgos, worth traveling to Spain even just to look at it. The family is on section 18. Any comments or help!-Daniel MDC