"In England we call them rolls of arms: in Spain they are known as armoriales — armorials — or libros de armeria — books of arms, and books seem to outnumber rolls as such. Of nearly 30 Spanish armorials recorded, at least eleven are books, and only one is definitely a roll. Nine are original productions, and six are known only from copies. At least eight foreign armorials contain compilations of Spanish arms." (Collins, W. T., Spanish Armorials, Coat of Arms, No. 161, Spring 1993.)
What does "...and books seem to outnumber rolls as such." mean?