The carved owls over the archway of Rockefeller Hall were completed in 1904 and are among the building's most striking exterior details. In the spring of 1906, Cope and Stewardson indicated that they were ready to design gargoyles for the new library cloister. However, in a letter of April 17, 1906, Thomas informed the architectural firm that she was not pleased with the carved decoration that they had already executed for the campus.
The owls on Rockefeller Hall have been very much criticized because the carving was not conventional enough and we shall make a very careful study of the carving on English college halls before we reach any decision in a matter that will so greatly affect the beauty of the exterior of the library.
The whimsical carvings, which can still be seen over Rockefeller Arch, were
not in keeping with the Jacobean architectural period being emulated in the
building. While Thomas was careful to indicate that the criticism came from
other people, it is clear that she wished to avoid historical anachronism in
the decorative sculpture.
Charles
Robert Ashbee (1863-1942), author, designer, and architect, was an important
reform-minded figure in the Arts and Crafts movement. In 1888, he founded the
Guild of Handicraft in London to educate craftsmen and to promote high quality
standards in craft production. As an early member of the British National Trust,
he made several lecture tours of the United States, speaking on the importance
of historic preservation. Ashbee made a favorable impression on M. Carey Thomas
when he spoke at Bryn Mawr College in 1900. Nine years later, she convinced
the Trustees of the College to contract one of Ashbee's favorite craftsmen to
execute the stone carvings on the new library building.
Correspondence between Ashbee and Thomas regarding Alec Miller's (1879-1961)
activities 
at
Bryn Mawr reveals that Ashbee acted as the young sculptor's business agent and
artistic advisor. In January 1909, Thomas provided Miller and Ashbee with photographs
of the library and its dimensions, which the two men brought along for comparison
on their drawing expeditions to Oxford.
I have been pretty fully into the matter with Mr. Miller, have paid a couple of visits to Oxford, one with him in person, & all the drawings sent you are based upon Oxford carving from the colleges of Merton, Wadham & New, also from the Church of Saint Mary and the Bodleian Library.
C.R. Ashbee to M. Carey Thomas
April 19, 1909
After
Ashbee's preliminary instructions and sketches and after careful study of the
carvings at Oxford, Miller executed designs for each gargoyle, which were approved
by Thomas before he traveled to the United States. On January 6, 1910, Thomas
asked Ashbee to send Miller as soon as possible. She wanted some of the carvings
to be ready in time for two important events to take place that spring.
Will you be able to let him come at the earliest possible moment, so that we may get as much time as may be? Our great Mayday Fete, a four years' festival, [will be held in] May and it would be very satisfactory indeed if he could get a few gargoyles carved by that time.
We expect to hold commencement this year on the 2nd of June in the cloisters garden, erecting a platform against the library, because President Taft will in all probability deliver the address and celebrate the termination of the twentyfifth year of the college and also, we hope, the raising of our endowment fund. We expect to have from five to six thousand people to hear him, and by that time I hope that at least enough gargoyles can be done so as to show what the effect will be.
Decorative
Carvings - Thomas Library 
Bryn
Mawr College
Campus Plan -
Hutton, Vaux & Olmsted
Collegiate Gothic - Cope and Stewardson
Details & Interior - De Forest
Paving Tiles - Mercer
Decorative
Sculpture - Ashbee & Miller
Bryn Mawr College Library Special Collections. September 21 - December 20, 2001