1901 film: The Cragg Family
A spirited film, showing the entire act performed by this most famous troupe of English acrobats, father and five sons. The Cragg family are famous throughout the world for their sensational acrobatic work and command the highest salary of any acrobatic family in the world, having received $3,000 per week on their last visit to America. The startling feats of hand and foot work accomplished by triple somersaults and marvelous hand and foot work accomplished by these premier gymnasts make one of the most wonderful motion pictures every produced.
Summary written by Edison Catalog

Their gymnasium was at no. 68 Kennington Road, London SE11

Adrian's En Piste, Les Acrobates (1973)
p35 Working in columns is, with the somersault, one of the specialities of Mat/Carpet acrobats. At the beginning of the century, this discipline was marked by a magnificent move by one of the most prestigious troupes, the Craggs who we cite also because they were also marvelous icarians (Risley/foot jugglers of people). In one part of their act, the Craggs, who numbered seven, formed two columns, the first, four people high standing on shoulders, the second, behind the first, with three people. When the columns were in place, the top acrobat from the first column threw a back somersault (saut perilleux arriere) and arrived on the shoulders of the top acrobat on the second column!

Truth or Fiction, Legend or Fact
By Pierre Couderc. Bandwagon, Vol. 9, No. 2 (Mar-Apr), 1965, pp. 12-13, 16-19.
Installment No. 7 the Teeterboard (La Bascule)
The only thing that can be reported with certainty is that, during the late 1890's and early 1900's, some of the great acrobatic troupes of the period remained "purists" and others, quickly sensing the possibility of more spectacular routines, wasted no time in switching from their old "ground-and-shoulder" routines to the high-lofting ones of the teeterboard.
At the time, such famous troupes as The Millettes, Heras, Montrose, Craggs, Bourbonnel, and a host of others too numerous to mention, remained "purists" and continued with their "carpet acts" while others such as the Glinserettis, Mezettis, Yacopis, Picchianis, and countless others, found it expedient to adopt the teeterboard.
By 1910, the traditional "ground-and-shoulder" acrobatics of the "carpet number" was gradually disappearing from our circus rings - and being replaced by countless teeterboard numbers, presenting spectacular routines which would have been impossible to execute by sheer muscular strength.

There are posters featuring them in the British Library’s Evanion Collection www.bl.uk/catalogues/evanion/
Some details here are courtesy of John Turner's fabulous volumes 'Victorian Arena; The Performers' www.circusbiography.co.uk