Adult models of authorship significantly shaped girls’ manuscript writing cultures. This chapter will consider the Barnacle, a manuscript magazine edited by the writer Charlotte M. Yonge and circulated amongst her essay group made up of adolescent girls known as The Goslings throughout the 1860s and 1870s. This manuscript magazine presents a complex negotiation of cultural identity vis-à-vis literary knowledge and writing ability. The aspirational status of the manuscript magazine demanded an extensive cultural knowledge of the girl contributors, but they often mocked the hierarchy of highbrow magazine culture in their writing and illustration. The Barnacle is a prime example of girlhood adaptation and transformation in the manuscript magazine form, which fluctuated between valorising distinctly male or female models of authorship that were entrenched by the mid-Victorian period.